My pup is in class right now. She started this week. She's 10 weeks old. This isn't just a fun run-around and socialize kindergarten. Our homework is to learn "wait" this week. I've already taught her Sit, which she has down cold. Down, which she has about 80%, and Come, which is at about 70% (not bad for a beagle!
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Puppies love to learn at this age. They think you're the best and they'll try almost anything, especially for a snack!
As long as the class requires all dogs to have their vaccines current and it's held at a location that is kept clean (no dog poop lying around, that sort of thing), I think you should definitely go!
Even if the class moves at a faster pace than your pup can keep up, you just move at your own pace and let this be a great opportunity for Gunner to get extra socialization. And, there's no reason you couldn't repeat the class again if it turns out that the class was too advanced for him this time.