Please make sure you let people know ASAP especially if they will have to travel/book accommodation. My husbands cousin told us the date of her wedding so we could book flights. She didn’t bother to mention then that our 2 kids weren’t invited. We had booked flights, holiday time etc around it and then received an invite saying adults only... I don’t mind she only wanted adults at all, but it meant we would be in another country, with our kids, and what would we do with them?! It’s an extreme example I guess, but just something to bear in mind.