It was a "Game"

When I was 7 or 8, there was a girl who liked to play this "game" with me. My parents never gave me "The Talk." The game involved sex. I didn't know what sex was or even if it was wrong so I went ahead and "played" with her. I didn't even bother to tell my parents, because I thought this "game" was normal. When she kissed me she told me it wasn't for real, that she was just "pretending" and not a big deal. Whenever she'd touch me she would tell me it was a part of the game or make some other excuse.

I'm turning 15 next week but I always have this feeling of guilt and being dirty.Especially now that I'm old enough to understand. I'm straight, but I feel disgusted with myself for going along with what she said. I feel robbed. Ive never confessed this to anybody before, and am still going anonymous because I'm still ashamed. When I go to therapy, I never talk about it.