Hey! I actually went to a wedding last Saturday and I was only on day 5 of my weight loss.
They had catered mexican food and I stressed about it like for 3 days. In the end I decided that it was a special occasion. I stayed conscious of not eating EVERYTHING I wanted but still ate a lil more than I wouldve at home. I skipped the horrible stuff like the chips, queso, rice, etc. and got the chicken fajitas and veggies and "healthier" options.
I just really managed my calories during the day and had a ton left for "dinner" and had quite a bit of leeway for myself. Oh, and I worked out before I went for a hour and then after I got home! haha
Good luck! You'll do fine. Just remember that its really okay to splurge on special occasions and tomorrow is a new day and stay on target.
I hope I helped a little bit! Have a good time! =)