The obvious but slight eroticism is magnificently enhanced by the contrast between the skin and the neutral gray tones of the background. Lovely face, dreaming eyes, and lovely line of the breasts, the belly and the tighs. Graceful hands and fingers as well.
Superb combinaison of cold tones, cold background, and lovely expression half the one of a young teen, and half the one of a woman... I would crop slightly the right side, in order to move the eye from the vertical centerline. A small detail.