Does anyone have any suggestions for a good time to start lining up for the Midnight Premiere of New Moon?

This is going to be my first midnight premiere for anything. My friend suggested we line up right after school (which ends at 2:15) but I think that's a little too early. What do you guys think? I'm really worrying myself about whether or not we are going to be able to get into the theater. It's snowing here and freezing and....... I can't get sick because I have certain medical conditions. Help please!! Thanks so much!