Girls: What does it mean when a girl winks at you the next time she sees you after having a GREAT connection with you?

Question

Girls: What does it mean when a girl winks at you the next time she sees you after having a GREAT connection with you?

I believe there has always been somewhat of a small "thing" between this girl and I in class, but the other day we got our first chance to really sit down one on one. We talked for two hours and both had a blast connecting, got lost in the conversation to the point that when I had to leave to go to work, I could tell we both didn't want the conversation to end. As I left she was smiling a huge toothy smile and I left smiling too. Today, when I saw her in class for the first time since that conversation, she "winked" at me for the first time ever...

What does that mean? Is there any chance that's NOT a sign of interest?

PS: She has told me that she showed a video of me to her mother, and has talked about me to two of her friends... not sure about what though.