Many years ago, a cartoonist shared this bit of wisdom:

Today, despite all the wars going on, few people seem to be growing up. Instead, the wars are excuses for coddling people who should be adults. No, not by age but by attitude.
Yes, age is the standard way of defining “adult” in today’s world. But that makes some very big assumptions about maturity rates, learning, experience, and attitude.
Somehow, in the States and most British-heritage societies (or rather, governments), the age of voting was assumed to be the age people became adults. So in the States, through the 20th century, the standard voting age of 21 was “adult.” As in “21, adult, and free.” (An old saying.) This was quickly enforced by laws requiring, among other things, that people 20 and under were not able to sign documents or take out loans by themselves. Oh, they could own land or other property, but only with a trustee. There were exceptions: driving, marriage, enlisting (or being drafted), and others.
Then in 1972, the federal voting age was lowered to 18. Suddenly, eighteen became “adult” time. But with many more exceptions – for example, driving at a younger age, marriage (in some States), and drinking and smoking. The longer we’ve gone on, the more restrictions on 18-20 year olds – and even on older people when it comes to renting cars, for example. (Under 25? Don’t try it.) And in the last few decades, as certain parties have sought more and more votes (especially those of easily-conned voters), there is a push to lower the age to 16. Without changing any of the prohibitions, of course: no booze, no weed, no driving big trucks or working in dangerous conditions. Or (no doubt) any of the privileges of juveniles: juvey (courts and jails themselves), relaxed rules, big school loans, etc.
All as bogus as can be, when you get down to it: the number of times we orbit the sun is not an indication, much less evidence, that we have (or have not) matured enough to act responsibly, wisely, or knowledgeably. Indeed, as government-run, tax-funded schools have declined in quality, an average 21-year-old college graduate today is less really educated and knowledgeable (relatively) than a 14- or 15-year-old 8th Grade graduate in 1924.
But we refuse to look at things (as a society) in real, quantifiable terms that are more complex than marking the days off on a calendar. As a result we have created and live in a dysfunctional society that is falling apart. And because so many people worship government in general, and democracy in particular, we have bound ourselves in red tape and process and rituals in such a way that we cannot correct this easily – and probably not peacefully or economically.
Something to think about.