AITAH for recommending to relax vagina during birth?

My (27M) GF (25F) got incredibly upset with me over text yesterday. She has a difficult time relaxing her vagina (she went to the gynecologist) and was worried how much it would hurt during birth. I suggested she learn how to relax her vagina more (PIV is very difficult for us because it hurts her so much) and she kept asking if I was serious and if I have any idea how much it hurts and that I should show some respect for my mother who has endured that pain. She went on to say that she can't believe how arrogant I can sound about things I know nothing about. I immediately apologized and had genuinely no idea it would make her so upset. Earlier in the day we met for coffee and had a nice time and she was all lovey-dovey over text and then just switched in an instant to accusing me of being an asshole when I made the recommendation, basically. AITAH for mansplaining?

Bonus question: We work close to each other and I suggested we grab lunch on Thursday. She jokingly said she already has plans with a co-worker (as if she's going on a date) and when I asked a couple of times "no really, what are you doing for lunch?" she said "no nothing I'm just kidding". Is SHE the AH for trying to make me jealous like this? I didn't bother with it and played it off but I hate when she does this, and we agreed a long time ago not to joke like that anymore (on her own initiative).