Please go.
Your son said it is up to you but I'm guessing that he would really like you to be there.
Things can and will change between now and October but from what I have seen (photos of a friend's daughter's wedding last week) , as only 30 people are allowed, social distancing was very apparent both at the wedding venue and also at the reception . My friend said that she really enjoyed the wedding - if only because it was a chance to actually see another human being !
Just be sensible, take your mask (colour coordinated with your outfit) for to and from the wedding venue, wash your hands and use anti bac gel (Boots have a great little Cath Kidston one that you can slip in your handbag as it's like a little flat cassette) and enjoy this very special day.