You'll be alright. Just be there for the experience. The rest of your competitions will be based off of this experience. In my opinion Grappler's Quest is the best competition around. Don't be concerned with placing. The first one, at least for me, was a learning experience.
If you're a competitive guy though...
BE AGGRESSIVE! I'm not a guy that likes to fight. There will be a few guys there that do though.
Keep it simple. Day one stuff. I review Eddie's 3rd option speech before every competition ("MTS 13 - Attack of Rento" first few minutes. Watch the whole thing but skip 15:00 - 18:30 minutes. It still doesn't sit right with me. Eddie actually gives a great mount tech at 13:00 min).
1. Stand and bang (not gonna happen at GQ...hopefully)
2. TAKE HIM DOWN!!!!
3. Pull guard! "And be wicked off your back. They have to talk about your guard like it's amazing!" "You've got to be a bad motherfucker to work off your back." "Or do what Andre Galvao does..."
But keep it simple. My first competition went take down, pass, side control, americana key lock. All of the last 3 matches anyway. I had to go through 4 guys. First guy messed up my world. I was like a deer in headlights. It was like I never took one BJJ class. My head instructor face palmed when I got up off of the mats, ha! I knew that was a bad sign. After that, I shook out the cobwebs and went back to day one. What I knew worked! Know what works for you and drill that progression like a mother-fucker.
I always remember those words though..."Be wicked off your back. They have to talk about your guard like it's amazing." You've got to be a bad motherfucker to work off your back." You want to get up off the mat and have your defeated opponent walk up to his guys and say, "Do not get in that guys guard!" Also witness the jaws on the floor. It's the best getting up from the mats and seeing all of the hanging jaws. Do yourself a favor and look around when you get your hand raised.