Why are her friend look at me?

I like this girl, and I think she like me too ( read my question) it have been a week now since I first met her and start it to like her.. Today I saw her walk with her friend like 25 meter away from me. Few second later, she say something to her friend and they turn around and look at me ( normal look) but she didn't turn around. What that mean?
Why are her friend look at me?
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