GSD's need a outlet for their energy, both physically and mentally
. Some are more couch potatoe then others
There are high drive show lines and low drive working dogs, research which line you want and speak to breeders and be honest. They should be able to help point you the right way
As for the shedding my boy just turned a year last week and is blowing his coat for the first time. It's actually not that bad but a good vacuum and broom are a must