AIO about not being friends with someone after they called me + size

okay i’m a solid size M in tops occasionally a L and a 10/12 in pants. my plus size friend tried to insist that i was not midsize and was actually plus size and i stopped being her friend over this. my bf thinks im overreacting and that she just doesn’t know how big she is. but i feel like no cause no how are you going to tell me what size i am and then try to push the narrative that im bigger than what i am?? so aio?