You have definitely come to the right place! Molly was about the same age as Tucker when I joined this board and I have learned SO much!! Unfortunately, it was lost in the crash, so keep asking questions for future new puppy parents.
As for training, we have only done the puppy class so far at PetSmart. I would recommend it. We had been in the store about 2 weeks before we picked up Molly, and were just talking to the trainer. She gave us lots of tips beforehand, and she seemed like she really knew her stuff. We made sure we signed up for one of her classes and so far so good. We are signed up for her to do intermediate training as well. If we have questions about anything she's willing to talk before or after class. The only thing I would like to change about their training is not having puppy play time.