Is my coworker interested or just being friendly?

I've been working at this restaurant for a month and this girl instantly caught my eye. I don't like her yet but I knew I would in the future the moment I saw her. I look around a lot pretty much check out every person at the restaurant, her a lot more often. At some point I noticed we started locking eyes (this made me introduce myself). It would almost always be me deciding to look at her only to find her already looking at me. I don't know if this means I'm looking too much. But I do know I've made a conscious effort to try not to because of a weird moment.

One day I looked at her saw she was looking at me and she looked away but I didn't. just to see what shed do. She looked back, then away then back, then she squinted kind of like "tf are you looking at dude?" Thats how I interpreted it. So since then I've been trying harder to avoid looking at her and yet when i do she's always already watching me. And now recently, its been happening more often (10 times in one day recently) and she's been smiling at me (not in a friendly way in my opinion but if she had a distinct friendly way I wouldn't even know).

Making a move would be very deliberate and very noticeable and I'm new so I want to be cautious of how I move in the workplace.

Is my coworker interested or just being friendly?
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