Dr. Jonathan Haidt and Greg Lukianoff, in their book "The Coddling of the Americann Mind," state their belief that current 18-19 year old colllege freshman, are only as mature as 13-15 yr. old just a short time ago.
I will posit that interest in cartoons, and fantasy make believe inform me that many never grow the Ef up.
And that lack of growing up is at the root of drug/alcohol addiction,, school shooting violence, online hostile and profanity laced misbehavior, etc.