WIBTAH? I am 9 months pregnant with my first child.

I Will be 40 weeks on christmas.
My MIL and their entire family meaning grandparents cousins etc. are really pushy about us going for christmas dinner. I specifically said that we don’t do christmas this year. I alerady cooked and cleaned for 4 family gatherings while 8 mo ths pregnant and it was not a walk in the park. Christmas dinner would mean that we travel 2 hours and i make all of the sweets for a 40+ people family gathering while being 40 weeks pregnant and i just hate that really. I also said from week 12 that we do not welcome any visitors for 6 weeks after baby is born. I feel like if i don’t start building up boundaries now it will backfire on me. Husband hates conflict and does not understand boundaries either so he is not any help in this case. Would i be the asshole if i don’t go?
Edit : baby was born today. Everyone is well.