My favorite Anime is Gunslinger Girl. It is about five cybernetically enhanced girl assassins about the ages of 11-13. The episodes, however, focus on their own personalities-- how they adjust from girl to killing machine-- and their relationships with each other and their handlers (men who take care of them and train them. The handlers are also shown trying to figure out the balance of training these girls, knowing they aren't normal girls, and trying to keep some aspect of their innocence intact.
MrBob