Well, it’s your wedding, so it’s your right to do whatever you want. If you really don’t feel comfortable serving meat and dairy products at your wedding, don’t do it. Find a caterer who serves ah-mazing vegan meals and go from there. However, if you know most of your guests are carnivores and cheese-lovin’ vegetarians, it may be in your interest to have at least one meat and one dairy option at your reception. This is especially true if you are not paying for your wedding. If others, such as your parents or your groom’s parents, are footing the food bill, don’t make a fuss about whether the menu should be vegan fare only.
Again, it’s your wedding. There are plenty of delicious vegan options for your guests to enjoy, even if they grumble among themselves. They can always eat burgers on the way home or the next day.