How should you contact someone via social networking?

[RaNdOm]

Okay so I have a crush on a girl, who doesn't go to my school, and I don't see her regularly, I actually only hanged out with her once with a mutual friend, and I am wondering how it would be socially acceptable to talk to her via social networking, btw I'm a freshman in hs and she is a sophomore in hs, although we are almost the same age because I have a summer birthday and I re did a grade in elementary school.

[Betty]

Most people use Facebook or Twitter.