When is the appropriate age to start teaching Wynstan how to participate in flyball? A friend of my has a flyball machine along with some agility training items, he said he has seen corgis competing before and said I would enjoy it as well.
Agreed with Beth. 12-18 months. You can work on the ground work, though. Get all of your obedience commands down pat. Also, you can work with tunnels, weave poles...things that are fun but don't require flat out running, jumping and climbing. Flyball is great fun and corgis seem to do really well at it.
By the way, one of the best things you can probably work on if you want to get into dog sports is a really focused off-leash heel. Your dog should stay on the side you put him on, left or right (I use the formal "heel" for left side, and an upbeat "Right side!" all run together for working off the right). You want him to stay glued to you while you change speed and direction. You can switch sides by turning in towards him rapidly--- if you spin inwards 180 degrees towards the dog and he started on your left, he will now turn around and be on your right with both of you traveling in the opposite direction. Your dog should stay on the same side if you do a tight turn with the dog on your outside. You can start with a treat as a lure and gradually fade the treat. Treat from the hand he's on (left hand if he's on the left, right hand if he's on the right).
He needs to be able to focus on close work before you start working on sending him away from you. I would just be careful of doing too much turn work with a growing puppy. Keep lessons to five minutes or so, a few times a day, and the majority of his time should still be spent in free play.
You can even work on heel work in the house. This is one of Jack's favorite things.
You can also work on getting him used to watching your hands, if he is not already. The vast majority of dogs follow hand signals better than verbal cues (they should know both so you can get their attention if they are out of eyesight). One thing I do is snap my fingers and point to move the dog where I want him. Maddie is slowly picking up on this too.
Wynstan's still young, so it will take a good long time to get where you want to go with him. Remember, keep it upbeat, keep it fun; he should think obedience work is all one big game, and a really fun one at that. Good luck!
Agreed with the others that you need to wait 12 months absolute minimum, and really 18 months or 24 if you are going to be on the super safe side. I'm not positive exactly when the Corgi growth plates close, that's something you might want to talk to a good breeder about. What you can do right now is find a flyball club in your area and start going to to watch and get to know the team. Flyball is done in relay teams, so if you start going to watch them practice now, they'll probably be more likely to let you on their team later, and you'll already know how to start training some things when Wynstan is old enough to start. I know the flyball club in my area does not allow dogs the first several times you visit anyway.