ask her whats up?? cuz what shes doing is giving you an open door .. shes teasing you without words just expressions and body movements i do it all the time at work lol.. so you need to leap before someone else does.. but if she likes you she will get frustrated and start to become more aggressive with you.. if you let it get to that point then ur blind as hell.. i mean come on what the worst that can happen she will say no? .. but i doubt it if shes playing with you like that..good luck