As long as you keep an open mind to all 10 of the sororities at UCF, and stick it out through the end, you have a very good chance of getting a bid with one of the 10 sororities.
The best advice I can give you is to tune out anything the other PNM's are saying about their favorite sororities. There are a few chapters that everyone may be buzzing about, and after the first round of cuts, there may be a few girls who are really upset and crying because they figured after one meeting that one of these was the sorority where they belonged. Don't be one of these girls.
Look instead at all of the sororities and find something to like about each of the ones when you attend their parties each day. Eventually, you will start feeling a pull toward one. You want to join the sorority where you feel like you can be yourself-- at your best or even at your worst.
I'm the first Greek in my family, too.

Good luck and have a blast!
ETA: Panhellenic should be mailing out a recruitment "101" guide this week, or you can stop by the Panhellenic office in the Student Union and pick one up.