Sorry - jsut had another thought! It might be a really good idea for your daughter to take up some kind of martial art.
This would give her both confidence and ability, and the whole point of martial arts is defensive, not aggressive. It may sound 'extreme' but they really can do wonders for the self-condifence of a timid or fearful child, and be very 'empowering'.
There's usually quite a good variety to choose from. Judo is pretty 'gymnastic' - lots of rolls and throws, so that may not be for her. Karate is much more like 'dancing' in that you don't go down on the floor! It's far more about blocking people attacking you, and then retaliating (if necessary) with hand chops and kicks. It's also very 'choreographed' as there are formal sequences of moves, again, very like dancing really, so it might appeal to a girl in that sense. I've done it a bit myself, and it was good fun!