I'm going to go with Ursula on this one. It's very common for adolescents to experience periods of attraction to the same sex. Generally, people who are gay have very little attraction to women during adolescence.
Your sexual orientation isn't definite yet, but if I had to guess, I'd say you're trending toward the straight side. However, if in a couple of years you find that you are still highly attracted to males, you will have to be honest with yourself.
True male bisexuals are actually fairly rare. When physical response to heterosexual vs. homosexual stimuli is measures, most men have a much stronger response one way or the other. However, there are a number of male bisexuals. It's nothing to be ashamed of, unless you start trying to deny who you are.