Is it normal that i prefer anal sex over regular with my girlfriend?

I recently began having anal sex with my girlfriend. I had never previously done it, or really even wanted to. One day a couple of months ago my girlfriend asked if I wanted to try it, saying she had positive experiences in the past. So we did, and it was great. I now find that I actually prefer it, think about it all the time and want to do it at almost every sexual encounter. I even find that if I watch porn the only stuff that interests me features anal. I feel infatuated with the idea. So, is this normal?