Harry Potter - What If I Haven't Seen the First One?

I know my girlfriend will want to see the new Harry Potter movie this weekend. I however, haven’t seen the first one as she has, and know next to nothing about the characters or the wizardry, etc., having never read any of the books, either. My question - will I be able to enjoy the sequel? How much would my viewing pleasure be enhanced if I saw the first movie first?

Well, I didn’t enjoy the sequel and I did see the first one (and enjoyed that one). But it will be somewhat difficult to get into things if you haven’t seen the first.

Much is referred to from the first movie and most of the competing alliances aren’t explained again. But then, there are several things that I didn’t think made sense and was told that it was clear to people have have read the books (which I haven’t).

My brother hasn’t read the books, or seen the first movie(yet), but he saw it this weekend and reported that he liked it and was able to follow it. (I’m jealous; I won’t see it for another week or more)