Bi-curious phase?

It's entirely possible that this is a phase. People go in and out of phases, and while some are genuinely bisexual, some people are only attracted to their same gender for a short time.

This is the part of my answer where I say that labels aren't really important; you are who you are, and you don't need to put yourself in a box for the convinence of others. But really, that's not too helpful. Some people find comfort in labels, and you can always change yours.

Basically, if you prefer the title of straight over bisexual, then that's your decision to make. Will this interest in guys fade? Possibly. Or maybe you're bisexual, and you just prefer girls. Which is a very valid place to be, might I add. I, for example, am vastly more interested in guys than girls, but I still feel that female attraction. Am I bi? Certainly. I just prefer one over the other. Just be who you want to be. If you find that being full-on straight isn't really how you see yourself, call yourself bi with a preference, or vice versa.

Anyways, I wish you luck with your decision. Don't forget that if you get it wrong the first time, it's an easy thing to just look at yourself a little closer, and find who you really are. Congratulations on finding the girl, as well. I hope I could help.