????
Do not bring past differences up. Say nowt.
A celebration is neither the time nor place to 'thrash it out'.
I doubt very much whether you would have been invited if the family thought that there might be friction between you and the other party.
I might have misunderstood but it seems from your post that you like to talk everything through at length, even if no result is likely.
Take my advice. DO NOT mention past squabbles.
Go, enjoy, be pleasant to everyone and fgs don't apologise/question or make any reference whatsoever to past matters.
My own take on it is that you find it hard to 'drop' things which others don't want to discuss.
Your confessed 'anxiety' should not make you walk out. You are not the central figure in this celebration so your thoughts on resolving past conflicts, do not matter.
Forget about YOU and enjoy being part of the happy occasion.
Remember, least said - soonest mended.
do you still buy BBC radio times?
What did you you think you would have by your current age that you don't?
Soops kitchen, a place of reflection, refuge and at times revelry.

