What kind of show? Breed show...local open show? I ask only because the show committee rented the space for the show and may not want non-entered horses on the grounds. Lots of variables.
If you are planning on showing him as a yearling or two year old I might wait until you are closer to the weeks of the show you might enter him in. I can't see all the activity hurting him. Just stay out of the way of exhibitors and make sure he is up to date on vaccinations. And don't leave him to go watch classes.