Is it normal that all of a sudden i am also attracted to men?

I am a 19yr old female who has been only attracted to other women my whole life. I would get hit on by guys but would only find it annoying. All of s sudden i am attracted to this one guy and we might even date. this is a very confusing time for me, my friends are all disgusted that i could even think about being with a guy. i don't want to mlabel myself because i don't even know what is going on. Is there anyone else who has been through this?