At first, I didn't get it, but this gets more interesting the more I look at it. It makes me think of Tiffany glass. So I can't help but notice the little smidge of shadow at the bottom edge.
I think I see where you are going with the white-on-white, but I think the uneven lighting on the petals detract from the overall image. Also there is some slight yellow fringing on the right side of the petals.