My personal experience and the personal experiences of most of the people that I knew growing up was completely different from this. True, there wasn't really an abundance of "young adult literature" that any of us read. Perhaps when I was 10 or 11 I did read some of those "YA" books. I read S.E. Hinton back then, but by age 12 those of us who read were reading serious literature. When I say "those of us who read" I'm talking about perhaps 30 students in what would have been a graduating class of 1200 (I moved after my freshman year of high school to a much nicer but smaller high school in a different town and state so I don't know how big the graduating class ended up). The rest of them generally considered that "reading" meant (based on their subgroup), (1) comic books, (2) Field & Stream, (3) Sports Illustrated, (4) Rolling Stone, or (5) the back of a cereal box. Most of them didn't even read what they were assigned in English class.

As a result, the statement:

Because it's good to read things that are relevant to your age group. Helps you feel engaged with others.

rings false to me. The things that are relevant to thinking people in an adolescent age group are generally the same as what adults find relevant, and there was no engagement with others to be had from reading books that were "revelant to [my] age group".