Well you could
be bi. Since you're still in puberty, you could find out more about yourself and you could turn out bi, even though you think you're completley gay right now.
Plus, it might just be a teen crush. Usually, when teens think they're in love and especially if they aren't in a relationship with a person, it's just a crush.
I know it's happened before, I've read things like this!
Maybe you should try this out, or talk to her about it. At least you'll be able to get your feelings out and talk about them to someone rather than having all those ideas in your head bounce off the inside of your skull
That's what I think anyway