lol i am no expert and not that much older than you to be honest mate (ive just turned 20)
like everyone else has said and as i said before, talking to her over the internet is a good way to break the ice a bit, but it is no foundation for any sort of 'proper' relationship, unless you just want a purely online version. Go talk to her, have a general conversation about shared interests, nothing to intense (dont wanna scare her away) and after youve done this a couple of times ask her if she wants to do something after school? Depending on her reaction to you in the convos of course
good luck let us know how it goes -x-