The clothing and attitude strike me as out of place in what appears to be a field. This is a thing that can work, but I'm not buying in this particular shot, for some reason.
The color palette is a bigger problem. The very very pale yellow is not playing well with the rich blues, to my eye. Also, her skin tones and hair tones are not separating well from the background.
Also, there appears to be some odd yellow coloration on her rightmost side. Is there a gold reflector or something over here? It's not an unappealing tone by any means, but it's a different color from the rest of her skin. Either color would be a fine, realistic, pretty color, together it looks a little off.
She is quite lovely. Wonderful pose, and so on, of course. It's just the background that's not playing well for me.