Klope3, it's a bit late, but maybe you can still use some feedback.
I think it's a good cover and although i'm familiar with YA fantasy genre I' not an expert in it. But i too think it works.
There's some nice contrast, lightning and colors in the illustration. As other folks have suggested, it's the face and proportions that need fixing.
It's a grown up's face. The hand and neck seem a bit too thick and powerful for my taste.
What I'd say also, for a fantasy cover, it seems a bit ascetic. Unless it's related to the story, the outfit could state "fantasy" even more by using details like embroidment, necklace etc.