Nice capture and lighting of subject for challenge. Focus seems to be on lips, focus on eyes would be better, with DOF to include lips. Seems to have a couple of hot pixels.
This is interesting. I don't see it as much as backlit but light from one direction. But having said that, it's still a pretty image. I think it might be a bit more pleasing if you weren't under her chin, but more to the side on an even plain. Since she has a rather prominent lower jaw area, the angle accentuates that. I like the lighting alhtough it's a tad harsh above her right eye.