My friend awakened me 😅😅

I've identied as straight by default, and I've only ever found guys/girls looks/personalities attractive. My friend asked me "how do you know you're straight if you've never liked/shown any interest in a guy?" And I was just like "uhhhhhh". I don't know what else I would be. My friends suggested asexual, but I wouldn't say that, I'm just overly casual, and I have no desire for sex with a man or woman right now. Maybe when I'm older? (I'm in HS) She really made me think "well.... how do I know?"