Why do I feel this way?

I'm 23 and moving out from my moms house in a month. I have been really excited about moving and am ready for some freedom, but as it gets closer I can't help but feel a little nervous and nostalgic. I've lived with my family all my life and now it will be different. I won't be far at all, and can visit whenever though. I'll have a roommate and I've known him since junior high but I'm still a little nervous we might get annoyed with each other. Maybe I should have stayed home longer and saved more money. Is this normal before a big change?