Vanilla has a really good point there.
I think I'm going to the same direction as you with my sexual orientation. Right now I would say I'm a Kinsey 4, so in general more attracted to women than men. A few years ago I would've said I'm a 1. I feel like this is changing all the time, not going back and forth though, but going towards total gayness. Now that I know it can change this much, I guess I should know it can go the other way too. One day I might feel totally straight again, who knows. I don't really believe that though. Anyway, just wanted to let you know you're not alone in this thought process.
We should just let go of the definitions! Although defining yourself as bisexual might be quite convinient, because it's such a broad term and can mean many things. You still don't have to date guys right now if that's not what you want.