Only because you're asking for critiques. I think there needs to be more value near the bottom of the piece, to add to the overall flow. I think adding hair, finishing what you can see of the hands, and neck, would really help out. Especially if you do it with some really nice, heavy darks. The piece is overall very light, and adding those parts in medium or light tone would, I think, only be detrimental.
Anyways, i really like it. You definitely have both talent and skill.
ps: this is just me, but loosen up! Messy is good sometimes.