If you catch a girl staring at you and she quickly looks down and does a double glance embarrassed what does that mean?

Like you look up and she is walking towards you eyes looking directly at you, your face and you guys make eye contact, after a few seconds she gets nervous looks down looks up at you again eye contact again and quickly looks down again.
If you catch a girl staring at you and she quickly looks down and does a double glance embarrassed what does that mean?
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