Some explanation of what maturity means seems in order.

Maturity is often defined as rejecting dependence and becoming a self sufficient adult that is willing to take on responsibility. That is probably in line with maturity in a state of nature. Humans however are cultural creatures and civilization is a state of interdependence beyond the tribal level. Thousands of years of cultural evolution has produced more abstract concepts of maturity often in reference to a religious or secular religious concept of virtue. In the West virtue became associated with Christian philosophy by default but was also influenced by Greek, Roman and other non religious philosophers. The time tested virtues for convenience sake can be taken from Christian literature. Seven virtues of historical prominence are listed below.

Humility against pride, kindness against envy, abstinence against gluttony, chastity against lust, patience against anger, liberality against greed, and diligence against sloth.

They closely align with Jordan Peterson's rules for life because he has humbly extracted them from cultural traditions. While they may seem trite, simplistic, and ethnocentric there is a certain universality to them. The same concepts of virtue can be found in diverse cultures slightly altered to fit environmental factors. What is interesting is that while youth culture rejects many of them it also seems to turn to alien cultures for virtues. Reflecting the biological drive of youth to alienate from the parent culture. This would in the natural state aid in gene dispersal but in the civilized state often a barrier to fitness.

The association between maturity and virtue is not accidental. Maturity is associated with wisdom acquired through the experience of how virtue plays out in the culture. Paradoxically a key component of wisdom is humility. Most of the foolishness and failures of the progressive movement are tied to a lack of humility and in the later half of the twentieth century to the domination of youth culture. The first half is tied to the brutality of youth as represented in the above mentioned novel "Lord of the Flies".

The question is if there was ever a time when humans were not brutal and the answer is that over time culture has reduced violence by delegating it to the state. See Steven Pinker's "Better Angeles of Our Nature". One of the virtues of maturity is patience that disrupts the anger of youth. The wise person is patient because they humbly accept not only their own limitations but the limitations on cultural perfection.

I have a lot more to say but I will return if there is interest.

Need you say more -got it in a nutshell!