Its done by points or wins. like if your dog wins a National sweeps is over a smaller show. Its all placement. While its true once a champion points do not matter, they place the dogs by the number of wins. I know I am being simplictic in my explanation but that is why you hear when you watch westminster " number so in so" in the breed."..
As far as what you want- that is up to you. If you want a easy start go with a seasoned vetern. If you have a good mentor to show you how to show- start with a younger dog. Its totally up to you..
Once you have a CH the dog goes into the Best of Breed class.
You know, I just have no idea why you continue to insist on displaying your ignorance. I don't know where you have been showing dogs all these years, but where I show dogs for the past 20 years or so, here is how it works, and anyone who goes to shows on any sort of regular basis KNOWS IT.
Points matter no matter how or where a dog is being shown. Dogs accumulate Breed points by how many dogs of their own breed they defeat, whether they are Champions or not. Breed points have nothing to do with Championship points. Dogs accumulate all breed points by how many dogs they defeat of other breeds in Group and BIS competition. Rankings are by Breed and All Breed, and are determined by the number of POINTS. It has nothing to do with the number of wins, it is the number of dogs defeated.
Sweepstakes carry no point value, neither for AKC nor for Breed points.
My advice to the OP is consider the 12 months old dog. Have the breeder go over the dog with you and point out what they consider the strengths and weaknesses of the dog. Then get at least one other impartial person who would be considered an expert in the breed to do so as well.
If health testing is important in the breed, then I would want to see results on that before I purchased a 12 months old dog, even if it is only prelims.