I'm 29 and living with my grandparents after my divorce- but i've always had animals- cats and snakes and bettas- a few birds- tame rats-
I think it's important to keep the tanks as clean and pleasant as you can so they have nothing to gripe about. Also make them as decorative as possible, which is easy with bettas.
Actually I think my dad got me my first betta when I was around six. He was blue and we fed him frozen shrimp from a pouch.
My son loves our Lulu- he calls her 'Lulu a blue goldfish' -he's almost 4