Well at 19 just last year they were a high-schooler. Lots of shit you have to do in that year maybe personal growth is a bit too much to add onto the onslaught of adulthood for some. It’s normal

I personally believe that you don’t start really displaying adult traits until after you’ve been out of school for several years. Working and supporting yourself is where you start to really learn the value of personal discipline.

School doesn’t really prepare you for life after school (other than giving you a base level of knowledge). You learn to adult when forced to.