Whoa...that choker totally rocks! No pun intended, but if there were some 'dead space' to the left, I'd have scored it a 10. I'm not a fan of 'centered' but I can still go pretty high at 9.
I wish there was a little more environment surrounding her for context. The head and shoulders comp doesn't seem to do the image justice. Nice job getting light into her eyes and I like your conversion. 6 from me.