Yea, I don't know about rethinking marriage but maybe the date. Assuming most of your friends are also Hawkeye fans, you can tell her this story from last year...
A bunch of my buddies were all invited to a wedding on the same day as Iowa @ PSU. The wedding reception turned into people taking their dinner into a classroom in the cathloic church to watch the game rather then eat and dance with the happily married couple.
I know September is a nice time to get married but the wedding will be much more fun if the guests aren't pre-occupied with a major sporting event at the same time. Unless of course you have the game on projection screens next to the dance floor (#dudewedding).