Annie, I have never heard of a peanut free school, but I work in secondary schools (I teach high school, so I am not sure how that would work with teenagers).
I think its a great idea, although I love peanut butter so it would be hard for me, but I have heard such horror stories about the reactions for some children (similar to yours).
I have to tell you that your wedding will be amazing and don't stress about the small stuff, just finish your school work and as long as you and your hubby and daughter are there that is all that will matter. No one will notice the little stuff, I promise I stressed about that stuff way too much but gave myself a deadline and what wasn't done at that point was kinda o'well in my book-and honestly no one noticed that a few things weren't done.
Is there anything we can help you with?