It's an invention of consumer society that doesn't exist in traditional Islamic or Western cultures. People should be done with school by the time they're 15. In traditional European societies, those who studied had their bachelors by the age of 14 and were teaching at 18 at Cambridge and Oxford. This is documented. Spending 12 years in school is an artificial construct designed to occupy time-space in which the society really doesn't have the ability to allow these people to enter the workforce because it is saturated.
Teenage phenomenon destroys human society.
A sickness of some Muslims today is that they've gotten into the whole age issue. Much like racism and sexism, it's identifying people with quantitative measurements. We don't know how old many of the sahabi were. It wasn't an obsession. Age in Islam is about having gray hair and not having gray hair.