What should I do in my situation? Thanks for all the advice in advance.

She came unto me 9th and 10th grade. She again showed me that before school started this year.
-2 or 3 times a night she would be looking at me when I wasn't looking then smile look at her.
-sometimes walk by with a couple of her friends whisper then smile at me.
-her friends came over to sit by me for no reason at all. starting a convo saying"she being too loud."
-first boy she went over to in a stupid game.
-I could tell when we talked that she wanted to keep it going.
-holds eye contact looking away.
-usually 1st person she would wave and smile to also get excited and happy.
-saw her on a date with a guy she just stared at me like a deer caught in the headlights.

she had a bf before Christmas. She acted different,but I could tell some interest. outgoing and flirtatious with other boys. the last 3 times I have sent her a text she has not returned it. her friends would just smile,and stare at me. I called her almost 6 weeks ago and talked for 11 minutes. I asked if she wanted to do something she said yeah maybe no hesitation. I asked if she wanted to go to the movies. she mumbled saying she had plans with friends.
only see her at religion class how she acting now. twice week.
-if I touch her she smiles more at me.
-getting food go sit at somebodies table literally already sitting down. she says come sit at our table when it was a small card table with already 4 people at it.
-next Thursday she called me back could not get to phone. I called her again 4 minutes later, but she never called back.
-she either thought I was lazy or shy cuz was like come on my name to her group. later she was standing next to me lightly turning her body to me. called her few days before not call back.
-last time this girl getting teased about texting late to a guy. she randomly smiled at me while that was happening. I called her few days before found out she was busy not call back.
she visited a gf over spring break whot my best friend is in close contact with. him and the girl talked the other night she said the girl I like was dating best friend. next day they talked again she told him she was wrong that they were just talking. like they always have. he then told her that me and him talked about her a few weeks ago. she asked him what did you talk about. he woudn't tell her. then after that he asked her if (my name) had a chance with her. she said yeah he does.