wow, this is beautiful, the anatomy is spot on, and the shading, don't get me STARTED it's so good. I would say the only two thing that really stuck out to me is that the closest front leg is a placed a little to far back on the torso, and that the (from Celestia's POV) right wing doesn't connect quite correctly, because, with the wing at that angle, you should see a little of the back of the wing because the wing would be twisted, so in the space between the neck and the wing, there should be a little bit of the back of the wing showing.

Other than that, It's absolutely gorgeous!!! ^^

<333