I agree... if you're going to take a body picture... get it all... if not... and you just want to take a portrait or a closeup... cut and cut like you mean it!
if you had left her whole body in, that would have moved her head up to fit into the "rule of thirds suggestion", rather than being right in the middle of the frame.
I personally love to see extreme closeups of kids making faces and doing the things that make them kids. don't feel uncomfortable photographing people, just have fun, and shoot shoot shoot!
that said... very cute... i'm sure her mom will love it.