i am confused about the girl i like , help !?

i got into a college(engineering) this year , its been 2-3 months.

i have a serious crush on a girl in my class , so i have been staring her for some time now....i didn't tried to hide it..

she looks at me too when i am not looking...

3 times she stayed in the class even after the period , and we and her best friend were the only people in the class...

she stroked her hair very seductively one time on purpose , when i was looking her

i haven't started talking to her yet , because it felt awkward to go and say hi....after all the staring

BUT HERE'S THE TRICKY PART

i was feeling little shy , starting the conversation with her.....so instead i sent her the FRIEND REQUEST on FACEBOOK , we have 16 mutual friends....

SHE DID NOT ACCEPTED IT

its been a week since i sent the request and she even changed the profile pic.....no other updates though...

have i interpreted the signs wrong ???

she is very shy type of girl....i am a fairly good looking guy , very slim though , didnt had any problems in talking to a girl before !!!

YOUR OPINION ???