That is fantastic, I think you have a great sense of light direction, shape and proportion! Her mane is shaped to perfection with the crown and body being spot on. The colors are niceand cool drawing her body to the front of the picture for the viewer.
Now if I were to pull at two things, they would be that the horn seems to be angled too far down [Atleast it appears that way] and she is missing some eyelashes. But again I think this is beautiful and I hope to see more work like this! ~Keep up the work.