Her screen name?

so there's this girl i like, and when i was on my facebook i saw her sn and added her to my buddy list. problem is, i dont have a facebook, so if I im her, its gonna look like i'm a total stalker if i have her sn. We're friends btw, so its not like we dont know each other. How do i go about this? I rarely see her outside of school and i wanna talk to her more. Should I just IM her?