Girl trouble?

k, so i like this girl in science cl. we r kinda friends, but only in that cl so were more of chums? evs, neways, i can talk 2 her an stuff, and she is always messin' with me. like almost everyday, she jabs the tip of her folder into my back. we laugh about this, and life goes on. but the trouble is, that her best friend is always staring at me in cl. not her best friend behind me, but me. (Iv'e proven this.) iv'e even looked back at her and said hi, but she looked away. she is NOT shy, so i dont really know why she's acting like she's shy. neways, r either of them interested in me? i kno, kinda hard to work with, srry)