You're going to be such a good Shepherd person! Now, don't get so worried and wound up in what you're "supposed" to do that you miss the sheer spontaneous joy and the little day to day mischief of your very first German Shepherd.
Truthfully, I have no idea how much puppy kindergartens and trainers are. They're definitely a boon, but I've got to admit I've only used training classes once, and that was when Purdue was 4 years old. By all means, take advantage of them because they will not only make things easier, they'll give you all sorts of opportunities to see your new puppy do all sorts of funny things that will only happen in that setting.
Just don't forget to have fun! Puppies are fun and they understand fun and yours will teach you the joy of all sorts of small, simple silliness and the importance of not being too serious.
He's only going to be a puppy for a very short time, so make the most of it.
Oh, and by the way, when he hits adolescence somewhere around 7 to 9 months, you'll think you have the dumbest dog that ever managed to walk.
It passes. Their brains start to function again and they become these amazingly intelligent and rational creatures and you wonder if you just dreamed the part where that doggy brain went AWOL.
With a German Shepherd, it's all about love and realizing that you're dealing with a rational, intelligent creature.