Wat should i do i am very confused?

ok so theres this girl in my homeroom and 5th period that i like a lot. i have noticed that everytime i turn around she is always staring at me when she sees that i see that she is staring at me she just looks away and when i talk to her her cheeks get red. so the other day i told her that i liked her on facebook and i asked her if she liked me back and she said no. but im not sue if i believe her. so wat should i do go for it or just move on to another girl?