When I got my first GSD (Harley), sadly, I didn't have this amazing forum to look to for help.
I got him at four months old from a BYB. I knew nothing about choosing a puppy. I didn't know anything about reputable breeders. He was not socialized at all. Poor boy was terrified of me.
We were inseparable after the first day together, but it took him a few weeks to warm up to my family. He would run to his crate, completely petrified with fear.
The thing is, I realize now that I've raised him the wrong way. If I knew then what I know now, he would probably be a much more confident dog. I've honestly ruined him. I hate knowing that. I can't undo the past, but I can use what I've learned to keep him happy.