OK I'm a sucker for old school. Not everyone does it and even fewer do it well. This is done very well. The tones and the light help set the mood. I'm drawn to the look on her face...sad, contemplative...the light shining on her legs should draw the eyes away from her face but here it doesn't. Some compositions work in spite of the rules they break.
I'm not an artist, but usually when I see monochrome, the first thing that is stereotypical for me to think about it "sadness/ melancholy." If you ever did another monochrome image, you should capture the real essence of a shoot which would be something along the lines of being surprised or content. Otherwise, beautiful picture and model.