It hasn't personally changed me besides changing the culture I participate in. For example, I started watching good anime because of MLP parodies made for some.
The best thing about ponies is that they brought me a lot closer to a friend that was sort of drifting apart. We make music together and for a little while, that was all we would do. MLP gave us something else to share and I'd say we've become best friends.
So yes, I guess My Little Pony did change me, if indirectly.