It's because you seem to be meshing two different styles. I actually really love the more 2d feel of her legs and the cloth, and I would be interested in seeing you incorporate that style into her face and hair... as it feels like a very classic, historically rich style. The hair is super contemporary and I don't fell that it fits with the rest of the image. The face is well done, but if you are going to render it so 3d with highlights and obviously rounded surfaces then I think you ought to do the whole picture that way...
Thank you for sharing your lovely work with us~!
keep it up
Good work!
But that right eye (from where I stand) is really sticking a bit out...