I hate being the center of attention. But I adore my MIL.
Sometimes I don't want the traditional things, and they are forced upon me.
Such as, we didn't want a cake at our wedding, and surprise! At the reception (very low key in a B&B) there was a cake! I was told: 'you gotta have cake!' No, if I wanted cake, I would have arranged to have it...

I have been forced to participate in other peoples events, like watching them birth babies, even though I would have just rather receive a phone call about it. As if, I am missing out by not having kids myself....

I would grin and bear your situation, because a party is just one day but the relationship with your relatives is ongoing.
Some people just don't understand the introverted nature of people who don't like parties or attention, they think; Who wouldn't like a party?!?

Your problem lies in a personality clash, I believe between introvertism and extravertism. It is usually the extravert that infringes on the introverts sensibilities, and not the other way round. This leaves the introvert, feeling
uncomfortable.