I think Doberman puppies look all mature and serious at a young age because they have to be. We're stacking them from a young age, and with such a competitive breed we need to be as sure as possible about their conformation before we decide to show them.
I will say though... the photos before and after that stacked shot involved a lot of jumping and general puppy silliness.
It'll be a loooooong time, especially since I think I'll need to buy another foundation bitch or keep something Stark sires (pending titles and health testing, yadda yadda yadda.) Breeding scares me - I don't know I'd let any of them go!