What does it mean when a girl does this?

Basically my friends sister always smiles and asks how im doing when she see me whether its at my friends house, her parents house or if my friend i go to visit her sister at her place. Lately though when we see each other no matter where it is she smiles and asks my friend how she's doing then asks me the same question but with a cheeky grin instead of the smile. I need to find out why its changed from her usual smile to a cheeky grin.
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6 mo
Edit... she also gives me a wink along with the cheeky grin
What does it mean when a girl does this?
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