We had our first fight long before we moved in together. Most of our fights at that time were centered around the fact that we weren't spending enough time together, so moving in really solved that problem, lol. Of course, we still have our little fights and disagreements, but nothing major. Just regular couples fights.
As for being afraid of change, that's understandable. Daren (my fiance) is the first guy i've ever lived with and I wasn't used to it at first. But you'll never know if you don't give it a shot. In my opinion, you really need to live with someone to find out if they're "the one". You know what I mean? Anyways, i'm probably just rambling now. But good luck with the living situation, i'm sure it will all work out. I'm not sure how helpful I would be, but don't hesitate to pm me if you have any other questions! ;-)