Beautiful model, I really like the freckles and the mysterious little smile. Kind of a Mona Lisa thing going on there. I get the feeling like she's waiting for something. Or someone. I've given it a high impact rating for this reason.
I don't like the blur on the loose strands of hair as much, it's like they're rebelling while the rest of the piece is quiet and peaceful. I would also have given her some more headroom, it's a pretty tight crop up there.
I like the rather cold choice of colorscheme, warmed up just a bit by the facial tones and the slight redness of the hair around her eyes and forehead.