Technically, Sunset Shimmer here is a pony. She may not look like it, but she totally is. There are all sorts of interesting cross-species debates that can go with that kind of transformation, along with pony Twilight and her sudden interest in a a monkey with blue hair, but that's not what this covers! We should totally dive into that some day though... it would be interesting.
ANYWAY, there is probably another Sunset Shimmer out there wandering around as a legit human. Will we ever see her? Where is she? What do you think?
Head on down below for some analysis from DrWolf on the subject. I have to admit, his theory is... intriguing, if a little easy to debunk.