How far do you need to travel?
Can you stay at home or will it involve a hotel?
Babies are more portable when they are tiny. I have to say I found the early weeks quite easy, they just lie there really, and need feeding changing. However, all babies are different, and all births are different. You could deliver late, and feel quite shit afterwards. Or have a relatively straightforward birth and feel ok by then.
Your undercarriage tends to feel pretty smashed up but is on the mend after 4 weeks, hopefully got a hang of feeding, and getting him or her latched on without too much trouble. Bleeding should have stopped by then, from memory that was about 2 weeks. It's heavy and I found that unpleasant, not usually a sanitary towel user.
If it's local, I'd say you'll attend, but be prepared to go for the afternoon and duck out early, or maybe not go at all.
Are you a bridesmaid? I'd suggest backing out of being part of the bridal party. Then there is no pressure if you need to disappear for a bit to sit in another room to feed, or take baby for a stroll to get them off to sleep etc. Plus you can choose what to wear, you don't want to be tied to some pastel dress that you can't feed from, doesn't fit etc.