Yes, once children "max-out" certain skills, they begin working on adult skills. I have one "child prodigy" who's already attained Level 6 Adult Violin skill, for instance.
Not every skill bumps up to an adult one, though. Maxing the physical skill does nothing (and that makes no sense), but maxing the social skill will lead to developing the adult Charisma skill.
From your experience, obviously fishing is another skill that can be developed and carried over into adulthood, if a child maxes out the mental skill.
