According to the USDAA, there are over 150 breeds of dogs, including mixed-breed dogs, involved in agility. Some breeds, like the Australian Shepherd and the Dutch Shepherd, are known for excelling at the sport. However, you should not let the fact that you have a Golden Retriever or a mixed-breed dog stop you from trying it. If your dog is playful and energetic, it will probably enjoy agility training.
There are many factors that go into choosing the right training school for you and your dog. Certainly distance is a consideration; however, convenience shouldn’t be the only factor that influences your decision. Other things like training methods, appropriate classes for your needs, compatibility of the instructor’s personality with yours, and certifications of the instructor should also play a role.
It's a good idea to proof your dog's training in different locations to prepare it for distractions. Invite a few friends over to cheer on your dog so it gets used to a crowd. You might also want to go to a training center or find local trainers who also have the obstacles set up in their backyard. If your obstacles are portable, you could even take them to a park.