I have a crush on someone other then my bf

I (16f) met my current bf (18m) last year in a science class together. We started talking and almost immediately started dating. We have been dating for 10 months now going on 11. We have never had a serious argument, and we get along great. I love him very much and can honestly see us continuing to date in the future. But this year I have met someone that i have started to develop a crush for, and I don’t know how to feel about it. I look forward to seeing this guy everyday at school. I don’t know what to do. I couldn’t imagine breaking up with my bf to get with someone else but i feel dirty liking someone that isn’t my him. I feel like a bad girlfriend even liking someone else. I would never cheat on him but I feel like I am because of it and I’m scared to tell him just because I know it will hurt him. What should I do? Is this common? And am i an awful person for liking someone else? (I know I’m young but I’m genuinely asking for advice, please no judgement)