I don't mind that her dress blends into the background, but I would like to see a crop above her legs, so that she becomes a part of her surroundings. Love the tone and her pose.
Nicely posed, I agree with Detlef that I would turn her a bit, so that right arm isn't just a thin slice. Great set, great framing. It looks like it was taken with available light in open shade, and she's blending into the dark railing. Either a lighter dress or a bit of sidelight would probably help. I wonder what she's looking at... well done.