Vegetarian-supply and demand concept?

You are one of millions and millions of vegetarians decreasing the demand not at your aunt's house but other places you go. When you are older and cook your own food, you will cook zero meat. It is not always a simple equation. Your aunt doesn't decrease demand because she always cooks the same amount. She's not a vegetarian. But by your being vegetarian, you decrease demand other places you go and you may interest other people in the idea of vegetarianism or veganism too. I guarantee if 50 more people showed up at your aunt's house, she would be cooking more meat. What happens if they all told her they were vegetarian before she went shopping? No extra meat. You make a difference in demand in the long run, along with every other vegetarian or vegan.