We have 21 year old twins. One is in the military so he's basically independent, working "full time", got his own car and has his own insurance. The other is a full time college student and working part time. We upgraded the vehicle she was driving (the one they shared while in high school) to a newer model vehicle and cover her on our insurance. Is that fair? You could argue that it's not but one is dependent, the other isn't. Such is life.
Added: she graduates next May so she has until the end of 2015 and then she'll come off ours and have to get her own. 4951