Am I Bi?

Lately I have found myself questioning my sexuality. I am a virgin and have never had much experience (I am overweight, not a quality that many people look for).

A while ago I was sort of dating a guy. We would go swimming in the pool in my back yard. At some point he kissed me and things started to progress. I knew nothing about sex at this point. One day he put his hand in my bathing suit and started massaging my breasts. I was intrigued as I felt a wierd tingle. He put his hand on my pussy outside of my bathing suit. This sent shivers up and down my body. My hand grazed his penis and I was surprised (I had no idea what an erection was). It was amazing to feel the heat from his penis surrounded by the cold water in the pool. As I stroked him he started moving his hands around on my body faster and faster. He pulled me into a hug and I could feel his erection pressing against my pussy. Even though there was no skin-to-skin contact we both had an orgasm.

I think about this experience often, especially when I masturbate. Since then I have become a skilled masturbator and have seen a fair share of porn. I have found that I love penetration and I love to see women being penetrated. I have found myself wanting to fuck women. I want to be the one they cling to as they orgasm. I don't know if this means that I am bi or a lesbian. When I look at people at school I find that I am sexually attracted to girls while even though I know that I want penetration. I want to know what everyone thinks. Am I bi or lesbian?

I also want everyone to know that your stories, ladies, are amazing. I have spent a great deal of time reading your stories and picturing your experiences. I would love it if you all could give me some advise about my sexual orientation.