My female GSD passed at 1 1/2 years old.
This was the first time I ever did anything like that and she had some major fear issues I had to work on prior to that.
I got a male the following year. He was 9 weeks old when I brought him home. I figured he would be able to pass much sooner because I knew what I was doing and he didn't have any issues I needed to work on.
As it turned out, he was 17 months old when he passed. He just wasn't mature enough. Maybe if I was a better trainer, we could have done it sooner.
Both my dogs are BYB dogs.