For what it's worth, a lot of people's sexual orientation is quite fluid, and moves around over the course of their life. Plenty of people here (including me) experience wandering orientation, it's pretty normal. I've always been bi, but since I began transitioning, the kind of men I'm attracted to has changed a lot (and the kind of women hasn't). At the moment I'm mostly into women, but more than anything it depends who I meet - since we're attracted to individual people, not genders, in the end, even if we have clear tendencies.
I'd say: let it be how it is, watch and enjoy, don't assume it's not going to keep changing, especially during transition where you're forming a new relationship with yourself (and being a teen!)