Hi, JH! I have an idea for you about the girl. If you get the opportunity again to sit near her, when you first make eye contact, smile & silently mouth hi & maybe give a slight wave. Then turn your eyes to your stuff (backpack, notebook, textbook, whatever) & appear focused on preparing for class. If she's interested, your subtle greeting will feel friendly & polite. She may take it from there in due time, when it feels comfortable. Do you think you could do this without feeling too nervous?