I think I would continue to look like myself, in centaur form, because I would get really confused by looking into the mirror and seeing something else. Possibly to the point that I would be startled, accidentally trout the floor and kick the mirror over when my horsebrain took over in a fight or flight fear response. When I traveled back in time, it would be 2003 Italy so I could immediately go find the place where cloning on
Prometea was done, hide in her paddock and freak some poor souls right the smurf out.
Since my super-powers would be superspeed a la "The Flash" and I have infinity money with which I could buy my way into competition as a racehorse and jockey, I would spend the rest of eternity winning the Triple Crown.
Oh, and my personal item would be a lucky horse shoe, because smurf you this is a great thought experiment.