Pretty interesting! I learned painting also from @Marco Bucci :D I think the colour relationship is pretty well done. Although maybe the size of the girl's head and hair could be a bit bigger, also the gesture, it's slightly more exaggerated in the ref, especially if you align the head and the chest edge you could see it. Also the exposure of the highlight can be a little more brighter. That's a problem of my painting as well, I don't tend to go very far into the "over exposed" region.