Does this girl like me back even though she says she doesn't ?

i am 16 years old i like this girl in my english cl. i talk to her once in a while but wen i asked her if she liked me she said NO !!! but the problem is that now she looks at me with a smile on her face. like for example i was talking 2 my friend b4 cl and i was standing by the door and she was looking right at me smiling. like one time i gave her a note and told her 2 stop calling me chi chi, because i dont like it. anyways i saw her walking in the hallway and instead of saying HI chi chi she called me by my first name and wen she said it she had a smile on her face. then the other day she asked me if i can lend her a pencil. then after cl she was about to give it back but she was about to call me chi chi then she smiled and called me by my 1st name. i don't what is happening does she like me or she doesnt or is playing with me and one time i asked her to get 2 cl just playing around & either she ignored me or is she mad at me or thinks i lost interest in her PLEASE HEL