Something about it seems off to me. I'm thinking maybe you should have shot from higher up because it looks to me like you're a little low which is causing her butt and thighs (well, the one thigh I can fully see) to be the closest to the camera and making seem bigger than I think they probably are. Or maybe have had her pose with a slight lean toward the camera which would have pushed her hips back and given a more slimming look. Or even a tigher crop cause from the waist up this shot is gorgeous, I'm just not sure it's all that flattering from the waist down.