how do i know if i like a girl?

i know this probably sounds super stupid but last year i had a crush on a girl and over the summer i thought i was over her and now i have no idea. My best friend is now best friends with her so we see each other a lot more than we used too but its still awkward. My friend jokes about like when i tried to help her find her textbook and my friend was like you didnt say thank you in a joking voice to her.