Is OTHER wrong in the post ? POST :  Im on mobile and also more importantly disclaimers bc I’m intoxicated bc it’s my 21st birthday!! So I genuinely am concerned whether AITA or not in this situation. 

So my closest friend took me out for my 21st birthday to get me drunk and she totally succeeded. So my dilemma is her mom who randomly showed up to drink with us got too drunk&amp; naturally her daughter offered to drive her home. Ok yeah makes sense and I have no issue. Then the vibe changed when we were walking up to my bffs car to drive her mom home. I was two steps away from the passenger door and her mom called “shotgun”, to which I jokingly said “but it’s my birthday!!” AS I got into the back seat. It seems relevant for me to say that her mom is a very large woman and fitting into seats has been an issue so she actually needs the front. I wasn’t even thinking about that aspect and her mom laughed so I genuinely thought no problem jokey jokes I’m messed up who cares. But now my friend is saying I disrespected her mom and was being mouthy and I seriously don’t think that I even semi came off that way to her mom or in general. I apologized but
AITA?