ther are 8 characters bit there’s only 4 route’s ,maby in the next update ther will be more (btw:David is not 18 yet lol)
It actually is, which is why Monchi doesn't want to make a route for him (which is completely understandable.)
Monchi's tweets about David:
As to why he's in College despite not being 18, it might just be because he started earlier? Or he was able to skip a grade? Those two reasons come to mind. There isn't actually an explanation for that yet.