I didn't mean take it off right after the ceremony. I would probably do the photos and all of that, then change into something else nice but baby-friendly as soon as I could, when my "duties" were done.
If your supply is OK, skipping one feeding won't whack it. Really. You just might get really super full, and if your dress is kind of snug, it might get uncomfortable. Then just nurse when things settle back down. And put in some good nursing pads in case of leakage.