first off what is a "frat"? ill go with thats a pub event.
Quote:
im just chillin now but im probably going to go to a [frat] later tonight, do you want to come?
"im just chillin now but im probably going to go to a [frat] later tonight and i know your comming tonight, your friends should come too!" sounds much better
talk to her tonight, but i advice you to read more about phone game and seduction in general. if she really was into you she'd blow off her friend or atleast bring them with her to you.
and what to say tonight... talk in general, connect, seduce her, plan something maybe (dinner or going to a nightclub)
,but most important make her talk about herself, because evryone LOVES talking about themself, so listen and ask things/talk yourself, but remember its not an interview.
good luck!