Get her the album "Bring it Back" by Mates of State.
I actually don't know how appealing they are to teenage girls as I don't actually know anyone other than myself who has heard of them or listens to them. Their music is very fun though in my opinion, and teenage girls love fun. Right?
Anyway, I think they're great, and the closest thing to 14 y.o. girl music I listen to. They have to be a safe alternative to self-loathing emo music or unrealistically sweet High School Musical tunes though. "Bring it Back" is one of my favorite pop albums.
SAMPLE:
http://youtube.com/watch?v=ERW1UfLalw4