Gosh... I am a studio photographer myself, and this is a 99.99% perfection for a children portrait. (Technical) One light, good exposed and composed photo. Details are very nice including the catch lights in her eyes. Her impression... I don't see absolutely anything wrong with this photo, other than a bit low contrast, and could be a bit sharper, but it could be the lens, not your camera necessarily... I don't know what else to say. The shadows are perfect.
Gosh, this is the kind of photo you see in magazines, and I don't get that much impressed this easily.
I am sorry, nothing bad to say about this, (Personal)I checked your photos and you do know your thing. Keep up the good work. If you need a negative criticism(!) I think you should ask again for someone else to look at this photo, because I can't find anything wrong with it... I am so so sorry... you are good LOL
Love, Love, Love this picture, everything works great for me here. Her expression, the soft light coming from the upper right corner makes her hair looks wonderful. Her eyes say it all. 10