I am "from" a large family - but really just have the same surname (as most).
I almost cannot remember the last time I saw many of this side of the family (paternal - not including the "pater"--- he is far far away) - my closest Uncle is now 86 and his wife not well with dementia. We have been in contact by letter and phone, until the last year when my calls seemed to be a nuisance, and I did not have an address for them to use. We have still been messaging a bit.
My cousin (of four in that family) - eldest daughter (of theirs) will always invite me at Christmas, and I always, politely, decline. She lives not far from her parents.
I just don't feel that I can go along and "blend in", after all these years (let alone my Uncle's little-concealed (even now) disdain. He once said that I don't go because I "want to be the centre of attention". That is not true at all, but he does have some dislike of me, even now (too long a story).
The thing is, I simply cannot hold up my end of the conversations (and I am VERY good at general small talk) when there is only me and there are only so many ways I can express interest, concern, excitement, sadness - when there are so many of them (potentially 12-20 for Christmas Day). It isn't that I consider myself to be of interest - far far from it. I do not, in fact, WANT to say ANYthing about myself......
But I know that even in declining, and if I say nothing that is rude, or dismissive, I am seen as unsociable (I probably am, these days) and not caring about this "side" of the family. There are some religious differences, and theirs always trumps mine, but that's always been the case, and would not be a deterrent.
I don't think I can properly explain as even that would be seen as me being self-interested. But I suppose I do worry that time is running out.
(I really do just try to get through this time of year, without bring anyone else down, and wait for it to be over. Family gatherings are not something I can do.)