should I move in?

I've been with my boyfriend for almost two years and we see eachother five to six days a week if not everyday. He's 21 and I'm almost 21. He has his own place and has since he was 18. I live with my parents and two brothers. My boyfriend has had a pretty rough life, but it's taught him that he doesn't want the life his family are living. He's basically got the basics of adulting down pat. I'm not going to lie, I'm kind of spoiled, but I still have a good head on my shoulders. I go to college, have a full time job, and pay my bills. He has said when I'm ready I can move in any time. I have strict parents and they say when I leave I can't come back. The problem is I'm terrified to leave the comfort of knowing my parents home is my home. And I'm scared that if I move in it will change our relationship completely and I don't know how I feel about that. But it's getting so much harder for me to leave him when It's time for me to go home and I'm ready to go up a step in our relationship. I'm just scared and in need of advise.