Open Question: I like her alot why is she so on and off?

I feel as if a girl this attractive won’t ever be into me. I really want her. I don’t know but I feel she’s interested and I feel as if she isn’t. I think she was last year because she used to bump shoulders with me and smile back at me. I remember this one time I was next to her when we were walking down the hall and she looked up at me and then back down a couple time and the entire time I was just smiling at her. I never thought of all of her smiling/laughing at me much and I never had guts to talk to her and I feel as if she got over me. Eventually she ignored for like the last month of school and then I regretted never talking to her. And for some strange reason she has her locker next to me. She’s in like 2 of my cla sses. I tried to act like nothing ever happened between us and to move on but she smiled at me a couple times ( I wasn’t staring at her or anything) Then she ignored me for a solid week. I think it was in the morning when I was walking to my locker and I saw her and a friend talking in front of our lockers then I just went to my locker and her friend asked me a question about why I keep an extra lock locked on my locker and I forgot what I answered and after HR the girl I liked asked me that question and I gave the same answer and she was like laughing/smiling/giggling and then I left because I was about to be late for class, but she was still smiling at me and smiled back.I never even thought of it that way until now… I thought she’s just playing with my head, but I still said hey to her the other day and she didn’t look up from her locker and said hi softly… I was like **** she doesn’t want to talk to me and walked away. I haven’t talked to her this week much and she pretty much ignored AGAIN and I also saw her pushing into this other dude and laughing and **** and I realized that I should probably just go back to not giving a ****. Should I quit or keep talking to her. I don’t want to regret anything and I’d rather have her reject me. So what should I do?

Open Question: I like her alot why is she so on and off?