W.P.
I used to be an actor etc.-you should go to a reputable agency and ask them who they recommend, what they're looking for in a headshot etc. Because the "style" of what they want changes depending on current trends and also what kind of "look" you, or in this case your child, has. Whatever you do don't go get headshots on your own and then go the agencies. They will very likely tell you they are "wrong" and you'll have to get them again, and it's expensive. Good luck.