There's a girl I'm friends with on Facebook that I talked to and she would always reply back. We had a small conversation, but one day all of a sudden she stopped replying to me. Every time she didn't say anything, I would give her some place and wait for her to reply, but got nothing. She would see the message though, so I stopped trying to talk to her. Today I go on my Instagram and I get a request from her that she wants to follow me. What does this mean and should I approve and follow her back? She I talk to her again?
Side note: We went to the same high school and had the same class together.