Bisexual?

Hey! I'm a ninth grader and it's the end of the school year and a close friend of mine who is a lesbian admitted that she has a crush on me. I have a short pixie cut and have always been mistaken for a lesbian and I've always clarified that I'm straight. but recently, maybe a couple months ago, I did think about the possibility of me actually being bi but I'm just not sure. A lot of my friends tease me about being bi and a lot of people think I am so I'm not sure if I'm just conforming to what everyone thinks and am just being pressured or if I'm actually bi. I don't really know what to tell her because I want to experiment and see if I am attracted to her but I don't want to hurt her. What should I do?