Question Author
So many insights for which I am grateful. Sorry maybe I didn't make it clear, these are grand-daughters. The oldest one has body dysmorphia which is a mental illness, not just shyness and nervous. I understand because, always being overweight from a child, no matter how much weight I lost I always (and still do), look in the mirror and see a fat person. She sees an ugly person, no one else does, but covers herself, mostly in black, as I have always done. Now I have reached the grand old age of 74, frankly I couldn't care less but it took me a fair number of years to get here. Being a bridesmaid would have been my worst nightmare as well.
I have always had a good relationship with all of them, and hope that somehow I can mediate between them, maybe some kind of compromise. I agree that the bride to be is getting totally, and un-necessarily screwed up about the whole thing, and definitely needs reminding that this is a marriage, not just a wedding, and it's not 'her' day as she keeps telling us, it's 'their' day. I am yet to hear her fiance's take on all this, but I will.
Fortunately, it's still some months to go before the big day, plenty of time to hopefully sit down and get some sense from them. And yes, I am very much of the view that 'if things can go wrong, they probably will', and it will be these things that you'll remember and laugh about in years to come. But oh, how impossible it is to put old (and wiser) heads on young shoulders.