If there is no breed class then yes AVNSC is the place to be. If there is no puppy class in AVNSC then simply enter the lowest age class they offer. It's likely that you will be in there with other puppies too. Remind the steward as you enter the ring that you have a puppy and he/she will help ensure the judge considers you for best puppy as well as judging you against the other age appropriate dogs in your class. HTH

If you were to win AVNSC Best Puppy then you will go forward to be judged with all the other puppy breed winners
Kindness is the language which the deaf can hear and the blind can see ~Mark Twain