I really feel for you!!! I was so nervous and was practically a total wreck before getting married, and even during the ceremony! Well, at least that's how I felt.
However, there are so many different types of people that I think perhaps it's hard to say whether your being nervous absolutely indicates that it is the right or wrong thing to do. In general, I think that having a sense of peace about making a major decision is a sign that it's the right thing to do for you. But on the other hand, some people have a tendency to be perfectionistic or have difficulty making big decisions in general. And then there are other people who normally don't have this difficulty, but for one reason or another, the particular decision of marriage itself just plain makes them nervous, no matter who the guy is. Perhaps it might help you to determine why you're nervous? Is it that you have serious doubts about the guy himself, or is it just that you'd be nervous no matter what, perhaps due to past experiences?
Whatever decision you make, once it's made (particularly if you get married), then I think it's helpful to rest in the fact that you have promised your lives to each other. This fact comes before any temporary "feelings" you may have after marriage, such as, "Oh, no, this is horrible!" or "This is the best thing in the world!" as of course feelings change from moment to moment. At least, this was very helpful for me, and as I said, I was totally worried about it even during the wedding, and even afterwords for quite some time, believe it or not! Yet now we're doing well and I really love being married to my husband.
I can remember so vividly how it was for me, so I really hope this weekend goes well for you! In any case, remember that God is watching out for you and will take care of you and your daughter no matter what you do!