I just joined the forum, so I feel odd to offer critique...however, the first thing that draws my attention is her posture and shoulder angle. I think if you worked with her to sit more upright and hold her shoulders back, AND perhaps have her turn her shoulders at an angle to the camera, the shot would be a finer display of your abilities here. I'm not 100% sure about how you should position her shoulders, but for sure, her shoulders square to the camera doesn't work well for this shot. Nonetheless, very nice job with the blacks