Love / I like one Polish girl. a 2 years ago I see her in part time job and I ask her out. [15]

I saw her in my part-time job and suddenly I felt for her. due to my introvert-ness, I didn't ask her or talk. but in the end, ask her out for more than friends due to fear of I will never see her more. Inside me, My curiosity increased to know her more and more, day by day. after my job, I slowly become a stalker on social media. our city is different in Germany. and when I started to know her from social media and polish girls, culture and all. I like her more and more. I started more focus on language instead of my study so I can talk with her. and then last year I ask her again for friendship. because might she not be interested then at least I could talk with her and know her as a person. I don't know how to impress any girl. she is the first in my life whom I felt for the first time. to impress her I try to many things that might didn't work. in starting, I thought she might be attraction, but it's been 2 years but still, I think of her all the time. even I try to see other girls also but my mind directly starts comparing them with her. she doesn't look like her. or I do not feel for them. I can't able describe what was that feeling when I see her. but that feeling I never experienced in my life. Please give me some tips on how should I talk with her and impress her. I literally feel her vibes, she is a little different compared to others in my eyes. there is not a single day when I didn't see her photo. she said she is a happy single girl, not looking for anyone. but I just want to talk with her as a genuine friend. I asked her 2 times differently, due to respect, I don't want to ask her out again but how can I talk with her about any tips? advanced thanks