Yeah, facebooks is a waste of time for weaklings.
Now continually posting and arguing on a
pua forum when you never actually go out or do any game, that's where true greatness lies.
Anyway, moving along from the derail...
If this is some girl you don't know adding people at random and promoting her skype on facebook she's probably just a cam girl or a catfish or some oddness like that. Maybe not, but I wouldn't put a lot of stock in it going anywhere. Just add her and ask her if she knows you from anywhere, see what happens.
In general don't stress about the content of messages you send, facebook, text or whatever. The less thought and effort you put in the better it'll generally go