ex friend/ ex girlfriend's girlfriend

well where can i start,
i used to be friends with this female and txt her almost 24/7 around 2 or 3 years ago.
I lost my phone and never seen her again untill last year when i saw her at her job at the mall.... while i was with my girlfriend at the time(which is when i found out they were friends).
So now i run into her at her same job almosta year later.
She works at an icecream shop, so i bought me an ice cream cone, all while flirting with her. i would of made a Number Close but i was being respectfull of her job because her boss was right there next to her the whole time and i diddnt want her gettin introuble.

So i have her on face book and i sent her a mssge:
me: yo icecream girl, whats your number
her: haha ice cream girl?
me lol ok my bad... Miss vanilla
her: oooh yeaa thats so much better lol
end of convo..

soo im just asking for pro advice....Would i be displaying dlv if i were to go one and respond with: "so are you gonna answer my question or what? lol"
Also im thinking since she didnt answer it the first time, then she is hinting that shes not giving it,,, OR maybe playing hard to get.
what do you think about one of these responses:

hmmm soo your being rude now is that it? lol
why you being soo cold girl
vanilla is my favorite flavor


normally i wouldnt give a crap about this but being that she is my ex girlfriends friend and i think id like to start dating her , this has got my game all sesitive about the whole situation. any advice would be apreciated, thanks