Girl's Behavior

Who is at fault here?

There was a girl who had a crush on me since school. In classes I had a crush on her too. She would stare at me. We would text each other. We would stare at each other and smile. I was very chivalrous to her. Once I was staring at her and smiling she reacted negatively. I started being cold to her in text. After that I would ignore her. She used to ignore me a lot too. I would always look at her expecting a hi but she would treat me indifferent and would never talk to me. I would sit behind her but she would always avoid me. I tried to make this girl jealous by sitting next to her friend. She put her head down and was almost crying. I tried to make her jealous again and again because of how she would treat me. But I would stare at her from far everyday. She would always act angry. I used to feel bad for her. One day she was sitting in next row. I looked at her. She thought I was looking at her friend sitting beside her. I leaned in to look at her. But she never looked at me. Few days she didn't talk to her friend but she then started to. But with me she was still mad. I remember 2 years ago I was with my friends after our classes. She was passing by me with her friend I turned looked back at her and called her name in low voice she pretended she was talking to her friend who was behind her and ignored me. Sometimes even i used to feel bad so i would ignore her. But sometimes I couldnt. In text she would always be nice to me but in person she would treat me like I am nothing. I started giving her one word replies on text. Sometimes she would comment on my pics then delete. She unfollowed me on insta. I sent her req we followed back and Today after 2 years we are in same college. I was expecting ignorance from her but she said hi. I said hi too. I looked at her with sad expression outside gate indicating how hurt I was. Should I go and talk to her or should I just leave it here? I've dated girls in between, made new friends etc.
Who is at fault here?
Post Opinion