no one gonna laugh at you at a meet less you act like an asshole.
99% of the guys at a powerlifting meet are the nicest guys you will ever meet , most would loan you a bench shirt or suit if yours blew out knowing that you might beat them in their own gear , they will help you get in your shirts/suits and spot you or even offer advice if they see you screwing up . being laughed at is the least of your worries .
dont worry about the other guys numbers, your battle is and always will be with the steel.
if you never listen to another piece of advice from pullinbig , listen to this one . the other guys in your weight class arent your opponents , the plates and the bar are your opponents . they are your best friends and your worst enemies .
you will never do a meet if you wait till you think your ready , if your benching 335 raw you will definately be over 4 in a GOOD shirt once you learn how to use it and train accordingly , 450 wouldnt be unrealistic if you are weak off the bottom and strong at the top . do your research invest in a good shirt and start training for a shirted bench .