I'm nervous about asking this particular girl for her number. Facebook isn't helping, obviously, and she doesn't have a crush on anyone. I recently graduated from the college she goes to (in fact, she lived on my floor for most of last semester, which was my last semester of college). Last time I asked a girl for her number it ended in a Facebook block (but somehow her profile seemed really fake). This girl, let's call her "Nikki", on Facebook, when I said "But I hope to make a trip to [the SUNY school which I shall not mention here on WP] to see some people soon" her response was "Nicole: oo let me know when that is!"
I'm stuck.
Is there an etiquette for asking a girl for her number?