You will get destroyed if you don't lift to your expectations. Powerlifting is about competing against yourself, that's it, who gives a fuck about the other guys. I'm 335 lbs, my last meet total was 1400ish I think, and I was very, very happy. The other guys in my class did over 2k, and they were cheering me on as I was them.
No one cares what you can lift at a meet, everyone is on the same team there, it's a different feeling and one that is very awesome and addicting.
Just make your opener very light, my buddy bombed out on squat, went to heavy regardless of what I told him, he was just scared as hell