It's alright. I wonder what it might look like if the vignette were a bit less-dominant, or if it were to be processed in a different manner. It just seems like the left hand side, as tirediron mentioned, has too much influence. I cannot quite put my finger on what it is that's bugging me; is it the extreme contrast between her white dress and the darkness? Is there just too little color? I dunno...I just think this could be processed differently,and it'd just come alive, so to speak.
Maybe with some texture, or a ragged border? Maybe lightened up a huge amount, and made into a dreamy, softy-focus-like, ethereal feeling shot? Maybe converted to monochrome?