Dog Obedience classes for Barf? Probably time I Guess

I have a three-and-a-half year old Golden Retriever that we got when he was two to keep my older Golden company. And I think it may be time to get him trained.We got him from a military couple who had split and she didn't have room or time for him anymore so he already had some bad habits.

One being not knowing how big he is. He is now about 90 pounds but he still thinks he is a 10-pound puppy. Found this killer deal on our Seize the Deal Spring auction page, so no excuses now right?