Is it normal for me to have a crush on a girl?

This girl I know(we will call her "stranger") is like the most popular girl in school. She is head cheerleader, always hangs out with the coolest people and I never thought me and her would become friends! One day our teacher made us stay back after school (but the teacher left) so it was me and her and I told her this story about my ccousin's two sisters kissing and how wierd it was(i was lying to see what she would say) so anyways it went on and was like that is so disgusting. Stranger says yeah it really is and i say how could you kiss your sister...or any girl! she stops for a minute and says "well i cant say not any girl"...BINGO! i think i have the answer i was looking for,...she may be bisexual. now the thing is i dont know how i can tell her that i really like her?
Oh yeah the following monday she had to stay after school and out of all of her "cool" or "popular" friends she asked ME to stay!!! and on our way out the building i some how got up the courage to kiss her on the cheek.(must have been a sudden adrenalin rush or something) but, y can i kiss her but not tell her i like her? What was her reply: Stranger-OMG!(she litterally said OMG) you kissed me!!" but the tone of her voice made me feel so happy cuz she sounded so happy/shocked.....How will i ever know?!?