The lighing is very nice except that you have her facing in towards the main light instead of the fill. This has the effect of making her face look thicker then it really is, and is not condusive to a portrait of a little girl. She is also almost sideways to the camera which makes her body look a bit distorted as well as means that for her to look at the camera her eyes are in the corners of the sockets so there is too much white on one side and none on the other sides. I am also interested in why you chose a horizontal composition and cut off her head instead of a simple verticle one with all of her head? This does nothing to add to the photo.
I love your background light in this, it is very effective. She is a great little model and overall this is a pleasant photo, but was very close to being outstanding.