For reference I have never really done anything to offend her. I'm on the autism spectrum so maybe she takes offense to some of the things I do like being blunt or indifferent (she's made comments about it when introducing me to someone, especially about me being awkward).
The scenario in question starts when 3 of my cousins and I are talking about going to a casino that's about an hour away from our house. Some of us had been drinking including myself (not my cousin who drove us). As we're about to leave I make a joke about taking a beer for the road and jokingly reach for one when my uncles GF chimes (lets call her Stacy) in and says something along the lines of "Don't do that, that's illegal and you're going to get in trouble" in a serious tone. I tell her it was just a joke to which she says "Yeah well its not a very funny one". I shrug it off, and walk towards my cousin's car along with the other 3. When we get to the car one of my cousins walks back to the house because he forgot something. When he comes back to the car, it turns out that when he was in the house, Stacy gives him not one, but TWO mixed alcoholic drinks for him and my other non driving cousin to drink in the car. After hearing about this I'm absolutely appalled that she would try to make me feel bad about my joke but to then so brazenly in an astronomically callous act of hypocrisy go and literally act out what I joked about that she claimed was so immoral and despicable. I tried to give her the benefit of the doubt but I guess for some reason she just has it out for me and my immediate family which I'm not even sure why since we've never done anything to offend her personally. Am I overreacting for not wanting to be around her or be particularly friendly to her when I have to be anywhere near her during family gatherings?