Maturity and "adults"

Howdy everyone! I hope everyone is doing good. I wanted to share something that is very dear to me. Something I like to do is try to think about our problems in the world, and what I can do about them. Something I have noticed is, people are big babies! And I do not mean this to be disrespectful. I mean, a lot of adults act like these spoiled children, don't they? Throwing fits when they don't get their way, being manipulated by someone with more power than them. Isn't it awful? You would think that some people should be more "mature" right?! Why aren't they behaving as adults, they are one after all. EVERYONE knows that when you hit 18 or 21, you are an adult and must grow up, after all, it is what we have been preparing for our whole life. Well. Let's take a look at that for a moment, if you don't mind. And here is a heads up, this is long and might read as a lecture. It is the summary of much research. If it isn't your thing, that's okay! I know it's not exactly what we talk about here. But please, hear me out a little.

Let me tell you (quite a few things) that I have learned about "Maturity"

There are three MAIN aspects I want us to all be aware of, when it comes to "maturity."

Physical.

Cognitive.

And Emotional (Social maturity is included here as well).

Here is the quick rundown of what I want you to know, first of all.

Physical Maturity:

The human body typically reaches full physical development between the ages of 18 and 25.

The brain, particularly the prefrontal cortex (responsible for decision-making, impulse control, and reasoning), continues to develop into the mid-to-late 20s.

Skeletal growth is usually complete by the early 20s when growth plates in the bones fuse.

Cognitive Maturity:

Cognitive abilities, such as abstract thinking, problem-solving, and emotional regulation, improve throughout adolescence and early adulthood.

The ability to assess long-term consequences and control impulses becomes more refined around 25.

Emotional and Social Maturity:

Emotional regulation improves with life experience, typically stabilizing in the mid-to-late 20s.

Social maturity includes the ability to form long-term relationships, take responsibility, and navigate societal expectations.

Reproductive Maturity (this is mentioned separately, but technically is physical how we talk about it here. I will get into the emotional aspect of it later):

Puberty marks the start of biological adulthood (usually between 10-16 years old), but full reproductive maturity (hormonal stability and peak fertility) is typically reached in the 20s.

From a purely biological standpoint, a person could be considered an adult once their brain and body have fully matured, which is around 25. However, emotional and social maturity can vary widely depending on individual experiences...

Okay! That was all something I think most of us know, right? The next part, it is just what I like to call "gravy info."

Human maturity is a complex process that involves multiple biological systems developing at different rates. Let's start to break it down further.

Skeletal Development:

Humans grow rapidly during childhood and adolescence, but bone growth slows down in the late teens.

The growth plates (epiphyseal plates) in bones typically fuse by the early to mid-20s, signaling the end of skeletal growth.

Bone density continues increasing until around age 30, which is when peak bone mass is reached.

Muscle and Organ Development:

Muscle mass continues developing into the mid-20s, influenced by genetics, nutrition, and exercise.

The heart and lungs are fully developed by late adolescence, though cardiovascular efficiency can improve with training.

Hormonal Stability:

Puberty triggers a surge in hormones like estrogen and testosterone, which regulate physical and reproductive maturity.

By the mid-20s, hormone levels stabilize, contributing to emotional regulation and overall physical equilibrium.

Are you guys still with me? Hang on just a little bit more! Next let's address Brain Development and Cognitive Maturity. The brain does not mature at the same rate as the rest of the body! What do I mean? I am glad you asked ( I like to think you did) Lets look at the bits of the brain!

Prefrontal Cortex Development:

The prefrontal cortex, responsible for reasoning, impulse control, and long-term planning, continues developing into the mid-to-late 20s.

This explains why adolescents and young adults tend to take more risks and struggle with delayed gratification! Have you ever noticed this?

Synaptic Pruning and Myelination:

In early life, the brain has an excess of neural connections. As a person matures, the brain refines itself by "pruning" unnecessary connections, improving efficiency.

Myelination (the insulation of nerve fibers) enhances communication between brain regions, improving cognitive processing and emotional regulation.

Neurotransmitter Regulation:

Dopamine, which plays a role in reward-seeking behavior, is more erratic in adolescence, leading to impulsivity.

By the mid-20s, dopamine and serotonin levels stabilize, allowing for better emotional balance and rational decision-making.

So where does that Emotional and Social Maturity I mentioned tie into all this? After all, Maturity is not just about physical growth—it also involves emotional intelligence and social adaptation. And, these things are tied together!

Emotional Regulation:

Children and teenagers experience stronger emotional reactions due to an underdeveloped prefrontal cortex.

By the late 20s, most adults have a greater ability to manage emotions, delay gratification, and navigate interpersonal relationships.

Empathy and Perspective-Taking:

The ability to understand other people's perspectives and regulate one’s own emotions improves with age and life experience.

Studies suggest that empathy deepens as the brain matures, contributing to more stable relationships and a stronger sense of community.

Long-Term Planning and Responsibility:

The transition from short-term, impulsive thinking to long-term, strategic decision-making occurs gradually as the prefrontal cortex matures.

Taking responsibility for actions and understanding consequences become more pronounced by the mid-to-late 20s.

Reproductive and Sexual Maturity is something that people who are "not mature" giggle about. And it is okay to make a silly joke about that stuff, humor helps us deal with really hard stuff. One of the hardest things we go through is puberty (Don't get me started on all the different kinds of puberty.) So let's talk about that for a minute.

Puberty and Fertility:

While puberty marks biological adulthood (typically between 10-16 years old), full reproductive maturity is reached later.

Female fertility peaks in the early 20s, while male sperm quality remains high until about 40 but starts declining afterward.

Sexual Behavior and Emotional Maturity:

While young adults are physically capable of reproduction, emotional and cognitive maturity plays a role in making informed reproductive decisions.

Emotional stability, commitment, and understanding of relationship dynamics often develop later than biological fertility.

Finally, lets look at Lifespan Perspective on Maturity. Humans do not reach a single point where they are "fully mature"—development continues throughout life.

Psychological growth, emotional intelligence, and wisdom accumulate with experience.

Some cultures recognize different stages of adulthood, such as early adulthood (18-30), middle adulthood (30-50), and late adulthood (50+), each with distinct cognitive and emotional changes.

In Conclusion (Oh I bet you are happy we are here, that was a lot of info!): When Does a Human Become Biologically an Adult?

If we define adulthood purely by physical development, it happens by the early 20s.

If we consider brain maturation, the mid-to-late 20s is a more accurate threshold.

If we look at emotional and social maturity, it varies widely depending on life experience and environment.

So, while humans are physically adult by their early 20s, true biological and cognitive maturity is best reached around 25-30, when the brain stabilizes, emotional regulation is stronger, and decision-making becomes more refined.

The legal age of adulthood (typically 18-21) was largely shaped by historical, political, and economic factors rather than biological or psychological readiness. Military conscription, workforce needs, and societal structures all played a role in setting these arbitrary age markers. But when you look at the science, it becomes clear that most people are still developing well into their mid-to-late 20s.

It’s fascinating-and heartbreaking-how society forces people to take on adult responsibilities long before they’re actually equipped to handle them. Things like managing finances, navigating complex relationships, dealing with trauma, and making life-altering decisions (like marriage, career choices, or even going to war) are thrown onto young people who are still in the middle of their developmental process.

And then, when people struggle, they’re blamed for "not being responsible enough," rather than recognizing that they were set up for failure in many ways. It creates a cycle of stress, burnout, and emotional instability that follows people well into adulthood.

If we structured society around actual human development rather than arbitrary age laws, we might see a world where young people are given more time to grow, make mistakes in safer environments, and transition into adulthood with real support. Imagine if people weren’t expected to have their entire lives figured out by 18, or if emotional and cognitive development were taken into account in policies around work, education, and even justice. The world would look so different.

It’s sad, but also hopeful—because conversations like this are how we start questioning these norms and imagining better ways to support human growth.

I want you ALL to remember, that you are not done growing. That won't EVER happen! Please, if you can learn anything from all of this, be kinder to yourself! No one is actually prepared for adulthood when they are "supposed to be." I don't think I will ever "grow up." And I hope you don't either. But you don't need to. Be your OWN adult, be your OWN parent, raise yourself the way you want to be raised and soon, you will find yourself to be the kind of adult you can be proud of. I hope this made sense! Love you guys!