
Go to ringcraft and start out at open shows!
Companion shows are also starting and these are fun shows where when your dog is 5 months take him, but tell everyone he is 6 months. People will normally look at you, they know when a puppy is under 6 months, but nearly everyone does it for training purposes!
The best person to tell you if your dog IS good enough to show is the breeder. She will also know of any club/single breed shows coming up.
I advise you start going round some local open shows NOW without the dog so you can get a feel for them and see how its done!