Baby Ariel is a teen, then go to high school, then..

I think I've only ever spied her once in my game. But that was quite some time ago. Never seen her since. If you stumble upon her, I believe the only way she will attend HS, is to play her. I have discovered by having more than one household in the game, that the ones I'm not currently playing don't go to school. This didn't change with HSY, sadly.