I disagree; one big problem we have is the multitude of different ages that we have that vie for entry into manhood:
One part of the problem is that societally we don't have a coming-of-age ceremony that acts as a psychological anchor-point/doorway for the transition; Jews, for example, have the Bar Mitzvah [done at 12] to mark coming of age, some African societies have kill a lion
, and so forth. The point is that these are concrete events that a man can consciously point to and say I am a man!
You’re right - the problem is not that “teens” are not mature enough to be responsible because of their age.
It’s that our society has allowed the concept of “teen” to be defined as a period of irresponsibility.