Is this actually showing interest or should I leave it be?

I've (33M) been working at this place for about a month, and I often go to this mall nearby to the grocery store during my breaks. There's this beauty store I walk past, and every time I do this girl and I lock eyes for 2-3 secs. I don't approach anyone, ever. I keep to myself and I'm quite introverted, partly because I don't like making people uncomfortable, and personal space is very important to me. Yet, today I decided to subtly raise my eyebrows at her when glancing at each other - I'm not used to smiling, can't force it - to which she smiled back.

Now, on one hand, yes, she could simply be friendly and doing that to everyone. On the other, I feel this could be a sign of interest, but I feel if I was to go up to her and ask her out it'd be a bit weird.

Does it come across I'm misreading the whole thing?

Is this actually showing interest or should I leave it be?
Post Opinion