So one time one of my childhood friends and I were fooling around with each other and we started kind of massaging each other's genitals with pool sticks. I was like 12 and he was around the same age. We had clothing on, but I got a boner from this. This was probably my only "pre-gay" experience before I knew I was gay. I felt really guilty about this is my early teenage years and even a couple years ago I was wondering if this somehow molded me to be gay. But I seriously doubt it now. The same friend is straight and it makes no sense why something like this would somehow influences someone's sexuality.
My advice is that kids do really dumb stuff sometimes. You shouldn't really ever feel guilty about this.