Is it normal to be in love with someone you don't know?

I met this girl on grade 9th, she was a Junior back then. The first day I saw her I got completely lost. All I could think of was her. I satalked her (no in a creepy psyco way lol) To be honest I never got to talk to her because I'm pretty insecure and I thought I wasn't enough for her. She was super nice with everybody and when we got to talk (which didn't happened a lot) she was nice but she treated me as if I was a werido. On my sophomore year (senior year for her) I broke up with my girlfriend because I was decided to talk to this girl. Yes, I still loved her even though I was on a 1-year relationship. Her last day of school I cried like I have never cried before. Because I knew I lost her even though she never was mine. I had to stay after school to make up a test but I couldnt go to that class. I stayed on a bench crying. How pathetic.
Why do I feel this way? Why am I in love with her if I dont really know her?
I'm now a Junior and I still think of her.