Yay, more Cat Valente fans! High fives all around!
Okay, on to the critique.
A centralized composition like this is by nature static-- which isn't necessarily a bad thing, actually. It depends on the mood of the piece. Deathless is a book on my to read list, so I don't know the emotional context of the scene, but what a portrait like this suggests is stability, nobility, strength, confrontation, and a certain statuesque inhumanity. It is not a composition to suggest vulnerability or softness, though it can be effectively *contrasted* with softness, which I think you've accomplished by use of the curls, the softness of the shading and features, and the fur.
The biggest problem I can see is that I can tell you copied and flipped her eyes to make them perfectly symmetrical, which adds to the "cold stone" seeming, especially with her blank expression. The highlights in the eyes are coming from two different directions, and neither of those directions actually reflect the soft, straight on lighting of the piece. The light is diffused as if through a fog, which means any highlights would be just as diffused.
I don't think you need to change the stylistic lighting, because that smooth softness is really lovely in contrast with the sharp lines of her hair and chin. I so think the fur could stand to have that same contrast-- sharpness vs. gradient. Right now, it's a little too blurry, and does not look like it belongs on the same figure.
My favorite part of the whole. Green, red and white are notoriously hard to use without looking christmas-y, and you've done a super job staying the hell away from anything remotely jolly. The really cool tones of her skin complement the green very well, and I'd pull a bit more of it into the shadows of the fur to unify the picture. Red shadows are creepy, and really add to the mood of the piece. Again, I'd pull a little more of that into the fur, particularly the shadows around her neck.
Overall, I really like the mood you were going for. it's eerie and controlled and powerful. I think with a few small tweaks, this could be a great piece. Ciao!