It's very tempting to answer directly your question about whether you are being silly...
A dog is a dog. Why would a dog even want to go to a wedding? Loads of strangers, some shrieking in horror, others, esp little people, hauling and pulling him around. Possibly unsuitable food, loud music. You'd also be on edge, whether he'll provoke an allergic reaction in a guest, bite someone (I'm sure you'll say he doesn't bite but no dog is a biter until the first time it bites) or someone feeds him chocolate, there'll be poop bags and food dishes to deal with.
Get a pet sitter to look after your dog and go and enjoy the wedding, knowing you're putting your son and his new wife first.