Everyone is on their own timeline! Ceetain "milestones" are bullshit ! It took me 5 years since highschool to get my associate degree. I also was a very very rebellious and defiant teenager . You can't act "older" or "younger" than what you are. You are simply the age that you are.
Maturity is a mindset, I know people who are 40 and act 16 . You’re still young , but old enough to know some things . Also as an FYI I would not use the R word on here. The proper term is having a disability .
Mentally challenged..Apparently same disabled is no longer acceptable either.
Sorry about using the r word.