If you're going to try, I'd suggest Caity Baser for new cheesy pop, and The Last Dinner Party for something slightly "cool", currently very popular.
There's some credible girl-fronted groups with a rockier edge too - Sprints and HotWax for example. I don't envy you having to try and decipher what works for an 11 year old though! Last year Sugababes were part of the 2nd wave announcement, so you might get something there?