How much time do you two spend staying over now? That should give you a guage. I wouldn't even have considered living with anyone else before I met my husband, but he moved me in with him three weeks after I met him. I just paid rent on my own place for the next year so I would have the feeling that I could go home if I needed to.
He was smart enough to give me my own space. I always had an office and he would not come in there if the door was closed. Then again, he's very quiet and I'm just as likely to write around him as I am in my office. At one point we looked at a large Victorian house with a garage apartment, but we just moved into a bigger house where I had an office and a library instead.
If you are that unsure, I'd say it's normal. I wasn't sure about anything, but it worked out because we are highly compatible and we have a similar desire for quiet and order. As to my Aspieness, he dealt with it as it came up and it did. I'd say we ran into things on and off for the first year. Of course we had no idea about Asperger's (Lorna Wing had just done her work then) or why I was like I was, but he wasn't emotional about all that. He's very logical himself. That's going to be a huge issue for you if she doesn't deal with your Aspieness in a logical way. If she gets all emotional when something happens, you are going to have a hard time living in a confined space with that.