I need to tell someone

It started when I was in the summer between 4th and 5th grade. My older "brother" told me that he wanted to play a game with me outside. I agreed, and we went outside to play. It was perfectly normal, until he told me we should have "punishments" for the one who lost the play fight. I didn't know what he meant, so I agreed. Starting that day, he started to rape me. I was forced to sexually please him, and I didn't know any better. At that age, I didn't even know what sex was. It went on for about 3 years. My mom caught him, and he forced me to lie about it, or he said he'd pin the blame on me. She then went on to promptly forget about it, as did my "brother". We eventually moved, and she forbid me from locking my door for years, and every day I had a panic attack fearing he'd repeat it again. It's been years and I'm still not better, and this is the first time I've ever told the full story of it. All I know is I want to get over this, because I'm scared to be near any male who is much bigger than me.