I would also suggest Tamora Pierce for the same reasons. Especially the books that are set in the world of Tortall. There are about five seperate series all set within the Tortall world but each follows a different heroine. I was 11 when i first found them and i loved them. Now i'm 25 and still regularly reread them

Aliantha Tamora Pierce is currently writing a series set in Tortall but a couple centuries before the main series about the adventures of George Cooper's ancestor, Beka Cooper, who was the Tortallan version of a police officer
