I work at a pharmacy, and while 90% of the our customers are in their 70's there are some good looking women who come in once in a while, most between 18 and 40 (I like some older ones

).
My question is, are IOI's given to you by women in this environment having to do with your job to help them, or is it actual interest? I've noticed once in a while a woman will toss her hair, smile at me, etc, when talking to me and I don't know what to make of this. Are they being simply polite to someone they are expected to talk to (I am usually ringing them up) or are they genuinely interested? At my job we look up their card information via phone number and when I ask them for their phone # to type in some of them toss their hair vigorously.
The reason I ask is because outside of my store clerk job, women very rarely give me this many IOI's.
And another thing, doesn't working as a store clerk automatically lower your value in a woman's eyes?
And if this is genuine interest, where do I go from here?
BTW, I'm 20 and never been on a date or had a girlfriend, so trust me I got a lot of work to do. My doubts come mostly from receiving what I thought were IOI's (hair tossing, smiles, eye contact) and then either being shot down or getting the phone # to hear the next day I'm not "their type".