I see what you mean, especially when you frame it that way. Is there a particular scene or dialogue that heavily implies that? Because that would never be what I intended =(
Jaja's arc revolves around the fact that he has a puppy-love crush on MC. Jaja being underage. He reveals his crush, but of course the MC in no cases, reciprocates that, other then they are flattered but Jaja is too young.
If you "pursue" Jaja, you can date him in the ending...but it happens years later when he is of age.