Obedience classes will help you teach the commands that he will need to know, it will also help socialize him, getting him used to other dogs being around etc...
If you plan to show in obedience it is a lot better if you enroll them into classes when they are puppies, and take classes until you are ready to show. Sure you don't have to show right away but I'd get him enrolled into a class right away. HE will learn SO many things that he will need to know for the show ring.

And most towns don't have their own obedience trials, you have to travel &/or wait for them to come near you. So later on you can show out of 4h, when you can drive to other competitions and when they come near you.