There is sharpeness in that image - some of her strands of her are nice and sharp - so I'm going to suggest that you missed focus or a back focus issue with the camera. Note that I never automiatically blame back or front focus as the explanation for a soft image, but this picture presents the symptoms very nicely.
So: which AF point were you using here?
If it was the middle AF point, this is what you focused on
Which might well explain what's going on.