confused about a girl i like...predictable i know but i really want some input :(

Ok so i met her through a friend and at first she was really keen to hang out with me, and shed make kind of flirtatious innuedo-type comments e.g she was telling me to do stuff for her and i was like "i luv how u just tell me what to do" sarcastically, and she got this mischevious grin and was all like "and i love how u just do it" , and she said it with a kind of sexual undertone. We also hung out watching this film for a class of mine, and she asked me if i was going to walk her to the station which sounded somewhat date-like. There have been quite a few things said like that, and she always laughed at everything id say and stare at me ALL the time in class or if we would be with a group of ppl. We went out to the theatre and stuff a few times and she seemed keen on doing more things, but then all of a sudden she just started turning down my ideas for hanging out...like saying she was busy and stuff. She still stares and makes the odd flirtatious comment when we talk...but she now runs off and doesnt accept my invitations to hang out.

Also, I didnt make a move before bc i thought she was very innocent, like she portrayed herself as quite the innocent catholic girl towards me so i didnt want to step on anyones toes so to speak, but i actually saw a photo of her through a friend of a friend in which shes all drunk and dressed up like a hooker....so yah...im not sure what to make of all of this....any ideas?