Buying for teenagers is always a bit of a struggle, I find it is easier to treat them like mini adults. I think they appreciate getting slightly more grown up gifts as they get older. Jewellery is always a good idea, these pieces are pretty and will look nice on a younger girl. Make up and nail varnish are another good idea, a close friend of mine has a little sister who wants to wear more make up and asked me to help him get her some bits for someone young, nail varnish is always a good place to start. We got her a palette of eyeshadow, some lip gloss and a little blusher,just make sure it is good quality.