My mother - a feminist - is annoyed with me because I'm not her shopping assistant.

Hello everyone,<br><br>I have been reading this sub for a while now, as a way of testing whether I was in the wrong or not. That's because I've been having a lot of trouble with my mother who - apart from being on her second marriage and having a 15 year long career - is a self proclaimed feminist. She brags about it to anyone who will listen, but somehow she thinks that it is my responsibility to go shopping with them on saturdays.<br><br>It used to be fun when I was under 10 (I'm 18 now), because I got pocket money and we'd buy me toys. But now I get 0 pocket money, because as my father puts it "I'm old enough to work for myself and get my own money". Which I did, during high school years - by selling my old stuff, offering services on fiverr, tutoring and so on - but I've stopped working on these gigs after the first year of university. Now, I'm on a tight budget because I have to balance work, uni and other stuff, and they want to make me go shopping with them, which I currently can't afford anyway.<br><br>However, I'm fed up with this because I'm going to have uni exams on December. I've been preparing for 3 months, but somehow they don't believe me when I tell them that I need to study (even though I'm top in every class). Shit's been going down ever since yesterday, because I was supposed to go with them but there was - somehow - a miscommunication and they went without me. They came back fuming and my mother shouted at me while crying, saying I "don't spend enough time with the family". I told her "that I can't afford to go shopping with you, and I don't have time anyway", which made her even more angry and she said I was being "selfish" and "I was raised by bad parents".<br><br>I'm really fucking fed up at this point, but there's no way for me to get her off my back. She's been texting me passive aggressive shit since last night, which I've been ignoring. I feel like I'm in the wrong because I've disappointed her and I have somehow failed as a son. What can I do? Should I just suck it up and go?<br><br>&#x200B;<br><br>EDIT: there are some comments saying I'm a kid and there's no way I could be 18. I said this because I wanted to be more relatable and vague, but my birthday is in January so I'm gonna be 19 in - what - 3 months? My mental age is probably that of a 12 year old, though.