If you are not used to drawing from a holster and re-holstering, do some practice at first with an unloaded gun. Best if you can have a buddy watch you. You want to make sure that you are not getting you support hand in front of the muzzle. It's easy to do if you need to get clothes out of the way to re-holster.
Also, pay attention to where your support hand is while drawing. It's possible to put your support hand out in front of you before the gun gets there--possible but bad. You might want to go through a few dozen draws standing in front of a mirror, going in slow motion. If you have a video camera you can put on a tripod, you can self-evaluate.
Just be sure you can safely draw and re-holster before you try it with ammo in the gun.
Oh, and when you get to the event, tell the range officer that you're new; he'll watch you carefully to make sure everything is safe.