Please help!!

I need help, I've been in my school for 3 years, right now I'm in 9th grade, English is not my native language so I don't have the best English, this year I realized that I had a crush on a girl, what happens is that I've never talked to her or her friends in 3 years and I'm not the kind of guy she talks to a lot, in the last few days I've been looking at her and I rarely see her looking at me, last week we played 2 basketball games in gym class And in both I had to cover her, in the second a boy wanted to exchange who we covered but she insisted that she would cover me, I don't know if it's because she wanted to be close to me or because the boy she wanted to change is the kind of boys that girls never want to have around them, yesterday I dared to add her on Snapchat and she added me back, but we didn't text anything, today at school nothing happened. I don't know what to do, please, I need help!!