Too many times
I was four when the older boy, maybe twelve, pulled me into a hedge, made me take off my clothes, and looked at my genitals. When he was done, I put my clothes on and ran home to tell my parents. They laughed and blew it off.
That must have been what gave my dad the idea that it was ok to molest me - that my mom laughed. When I was five, he told me that he was going to teach me about the birds and the bees. For years he raped me on an at least weekly basis, only ending when I turned 10 and puberty started. He was afraid, he said, of getting me pregnant. I was afraid of breaking up my family, and I was afraid of going into foster care. So I didn't tell.
It must have been apparent, though, because pretty soon boys my own age were molesting me. One molested me for about a year, touching me, making me take off my clothes, give him blow jobs, etc. He would threaten to tell my dad what he was doing, and I was afraid if he did that my dad would be very angry at me. So I didn't tell.
When I was 13 another boy tried to rape me. He told me he was going to have sex with me and he took off my clothes and fondled me. I let him because I was afraid, and because my dad had taught me to do that. Fortunately, someone walked by the shadow we were in and he got scared and stopped. Our parents were friends, though, so he probably would have succeeded if we hadn't moved away.
When I was 20 I went to a camping event with two friends, a married couple. It was far from home and raining really hard, so we agreed to sleep in the back of their pick-up truck. I awoke to find his hands on me. He was pretending to be asleep, but he wasn't. Slowly he put his hands in my underwear and then he moved my hand onto his penis. I was petrified - what was I going to do? It was raining hard, and the rain was cold - was I supposed to leave the car and freeze in the rain? So I let him. Then his wife woke up and I broke and said what he'd been doing, and he said he had been asleep and thought it was her. She believed him and stopped being friends with me.
When I did tell my mom about my dad, she hung up on me. She asked me what the point of me telling her was, since she couldn't do anything about it, and she accused me of lying. She called him up (they're divorced) to ask if it was true, and fortunately he admitted to it. But the shame of being doubted by my own mother still burns.
All of these things were not my fault, and it was all wrong.