My grandmother bought tickets for her, my mother, my sister and I to go to some hotel to get tea. Tickets cost $120 per person. My grandmother went ahead and made these plans and bought the tickets without even consulting me.

I tried to set a boundary today and I told my mom that I will not be able to go. The semester is coming to an end and I will be graduating soon. I need to put full focus into my final exams and other obligations. This greatly upset my mother, who then forced me to pay her $120 for a ticket that I had no say in buying to begin with. She started going off on me saying that I can't "pick and choose" when I want to be a part of the family.

I come from a family where the women are pretty narcissistic and they cannot handle when I set boundaries. Making plans without my approval happens all the time and I can't stand it anymore. So Reddit, AITAH for setting this boundary? Should I be obligated to pay the $120? (I already did to get them off my back).