I ate my girlfriends ass and ended up enjoying it

Im Jordan, a 19 year old college dude. I have a girlfriend named julia, shes 18. Shes crazy hot and attractive, and im very lucky to be her boyfriend. A few days ago, we were making out, and it got to the point where she asked me to eat her ass. I refused at first, and we had a little debate over why and why not. Eventually i got sick of her begging and gave in. I licked her you know what, and i ended up liking the taste, and feeling. I didnt want to tell her that, and every since then shes been asking me if i wanted to do it again, but i kept saying no, despite the fact that i actually want to do it again. I dont know how to tell her without looking stupid.