My she is rather sleek, nice work, now will you be drawing a grown up version of Nightmare Moon? (Not that I think it's possible since Nightmare Moon looks like an adult then and there! Still when is an alicorn an adult right?)
I wish you good luck then! Although taking a quick look at your profile you have done some nice work with the others so I am confident you'll do great! Now if Nightmare Moon looks so much like an adult what would she look like if she was younger?