How will a girl act around a guy she just met, and thinks is attractive..?

so im at a new job, and just met this new girl, while i was talking to a co-worker, she walked by and said hi, said her name, and i said hi, and said my name but she seemed to kind of move on, like she didnt lock eyes with me, so i said alright,(shes a very cute girl btw) to myself, and didnt interact with her, only to ask a question when we worked near each other, and she seemed like the type of girl that usually is in control of things, and probably was the class president or team leader in sports in highschool..just giving an image. anyways, later on, when the group of us young people were together she asked me what grade i was in, i just graduated, and if i played bball, and said i looked like a kid she knows, but it wasnt an excitement in her questioning, she looked at me, but not like other girls do.. and even her friend that was with her didnt interact with me that much, i dont know if its cause thats how they are, or maybe im just too nice, but yea, i didnt ask her anything the whole night, and kind of set my sight away from interaction with her, just to see if she was an attention lover, she mentioned a boyfriend she had when talking to the group, and i saw her looking at me only when i was talking with someone else.. anyways, we left, and i was outside waiting for my friend to drop me home, and she and her friend just walked by, but my back was to them, but i looked back.. i feel like maybe i should have been nicer, but at the sametime i felt like i know exactly what girls like her are like. but anyways, would she have acted differently IF she liked me, despite she has a boyfriend and all, lol? and should i play the ignore to get more card?