I love the composition and the natural lighting. There is a great glow on her face that does not overpower her or distract from the image. I would have probably repositioned her shoes farther to the left, behind her feet, or even had her hold them by the inside of the heel with just the tips of a finger or two.
Great choice in doing this in black and white. The image has great contrast with just the right amount of grays in my opinion.
Although it looks slightly like she is focusing on her stance or pose, (like holding in her stomach,) it is still definitely a natural look at a glance without being awkward.
Lovely model and setting.