Does she like me? Why didn't she txt me back?

this girl use to look at me all the time and i tryed to talk to her a few times. but she didnt say much I liked this girl for a while and she used to look and stare at mr all the Tim in the hallways and in lunch...than one day i got her number from her friend and i txted her and she didnt text me back.....now for the last few weeks she been doing these werid things around me so what does it mean?? why didnt she txt me back?? should i text her agin??