Teenagers are fine, but not with excessive fan service.
In my example I asked for Persona in college.
Joker, Futaba, Makoto, etc being 17-20 wouldn't change too much, but would make things less unsettling
A character being an adult doesn't make sexualization suddently okay, especially if only female characters get sexualized and if they get sexualized in humiliating ways and with other characters force them.