I'm sure you can do better. Try drawing some more so the animation can have more frames and be smoother. The character design is not ugly and the wings looked quite nice as well but the stiffness of it just ruins it. In a transformation sequence such as this there needs to be movement. You can make the hair and dress flow in the wind ,slowly changing colors or flashing to reveal the final results. I guess that is fine that the wings just kinda appeared but the impact would be much greater if they came out of her body and her body language showed that there are some changes occurring. Keep on animating! You will surely improve.