This might be a bit complicated question but how do you age the RH characters? Because I can the powerpuff girls are teens but wouldn't jack be quite older? And wouldn't Dipper and Mabel be aged up to attend RH since it's canon that they were born in 1999? Or are there no rules?
ages of Most Child characters are Roughly Inspired by the age they were when the show ended
The pines twins aren’t there because they’re canonically 13 when the show ended This Year
but don’t put too much thought into it
some characters from shows LONG ago are still young
Jack was 14 in XS and is 18 now
Snow White is a student because she was 13 in her movie and in RH she’s only 16 as if she was pulled out of her own time (Yes electronics confuse the hell out of her)