so sick of her mouth😒

Okay I'm in baby #2 (yay!) I'll be having her vaginaly (just like my first) unless there is a need for c section. I was having a normal conversation with my stepmom this morning about it. She was in the room when my son was born.  Then she turned the conversation into c section vs vaginal birth. She said she so glad she had c sections (due to emergency reasons) because her vagina is tight and pretty and she positive it's tighter than mine🙄. I told her the vagina bounces right back since mine was surprisingly tighter than it was before I had my son, and that the only thing that really changes down there is the cervix. She got super bitchy and defensive. I find her ignorance very appalling. She's trying to fly over to Texas from Hawaii to care for my son while I'm in the hospital delivering my baby girl... But I'm worried things are gunna get dumb between us again. What should i do?!?! Things get bad between us a lot.