I was around 7 years old. We were having a normal family dinner, (my parents were already semi vegetarian but would eat meat sometime in the week), so this time dinner was meatloaf, I was about to eat it, then suddenly I thought no. I stood up in my chair, looked at my parents and said "how do you want me to eat this? Are you crazy? Cows are animals! I can't eat an animal, that goes against my rights! (yes I said 'rights'). After that night, my parents decided it alright for me not to eat cow's meat, but once I again I refused to eat chicken and then fish. They let me eat vegetarian. My mother eventually became a vegetarian. Followed by my dad. Before all of this happened, I never really enjoyed the taste of meat, I was always giving it to my dog under the table, or hiding it in in any place I could hide it in. It was a hard time getting me to eat meat. So, I think a big part of why my parents decided to let me go veg was because they eventually quit trying to get me to eat meat.
After that, when I was around 15 years old I watched the documentary Earthlings, which immediately made me want to go vegan. But my parents wouldn't allow it. Mostly because at that time I was having real bad health issues and they thought a vegan diet could send me to 'the other side'. Finally at 16 things got better for my health and I graduated high school, found a part time job, and could afford a vegan diet. At first my doctor was hesitant in allowing me a vegan diet, but I wasn't about to give up without even trying. I became vegan (not only for health but also for ethical reasons) and proved my doctor the diet was actually doing better to my health. One proof was that my cholesterol level had been decreasing (it was quite high, which is something really funny, no one could honestly think a person with anorexia could have high cholesterol, I did). I was eating (which as you can imagine, after anorexia can be quite difficult), and I felt great. I'm now a happy vegan.