It sounds like your mom is scared that you will develop an eating disorder from veganism. If you do not have any history of eating disorders, then she has no reason to worry. Otherwise, you might suggest that you seek help from a dietitian as you transition into a vegan diet. If your parents are really stubborn, you could do vegan-until-4 for a while and gradually go full vegan. Ultimately, they can't decide what food you're eating. Just stop eating foods that your parents make if they aren't vegan. Ask your parents to make a side salad with dinners and only eat those. My parents weren't super supportive when I became a vegan at 15 but I just did it anyway. Buy your parents some books to read about vegan diets (and all the health benefits!). Offer to pay for some of the produce if you can. Get a job so you can buy bananas ;). In my opinion, you're already a vegan if you want to be. I had "vegan brain" my whole life but never ate vegan until last year. They can't stop you if you're already there.