Nice values! How did you get the darks so dark? Did you use charcoal?
I think that overall it looks really good. Especially the values. I was admiring how dark you got it. There are some discrepancies in the features, but I think it's mostly just that her eyes are too high on her face. And because of that, her nose is a little bit too. Her mouth is also turned a little bit to the right. It's in the right place, I think it's just that the lips need to be a little fuller on the left side? All in all though, I think that those are pretty small things. You picked a hard angle, she's only slightly turned...yikes, that's just asking for trouble ;)