I agree with those who are saying to keep her. I have never owned a OOAK pony but I have left behind some pretty ponies in markets and I regret it! Collecting MLP, especially the older gens, is so special because a lot of the time we only have one chance to have a certain pony. This is especially true for any Nirvanas! I think you should sell some that aren't as special to you. Best of luck, I know its a tough decision.