I think a lot of the older members of this site, while I think they're great and have way more valuable experience than most of us, are a bit behind the times.
All this never text/IM/Facebook stuff is simply behind the times. I know girls that pretty much don't answer the phone (they barely even buy airtime minutes) regardless of who's calling, but they will gladly text. Most people want to be somewhere private, quiet, and not busy before they want to answer a personal call, where as they can discretely text anywhere, any time, at their convenience. As for lacking balls, in some ways it takes more - if you say something risky and it totally flops, it's a lot harder to smoothly back out of it when she has the message stored.
I've also managed to set up dates and sleep with girls who I've never spoken to on the phone, purely in person and then follow up online or by text.
Good or bad, when not in person young people prefer non-spoken communication these days.
Anyway, just add her, but don't be a tool about it. If there's some event/party you're organizing you can send her an invite, and chat a bit if you have something to say, but don't be a loser who's always on her profile 'liking' everything and commenting on every photo.