If you want a puppy, be sure you have the time and patience to deal with housebreaking, crying at night, chewed furniture and other damage a puppy can cause daily, as well as having no real time for much of anything else you enjoy doing because you must supervise the puppy, for months. Another point about puppies is, you never know how a puppy will look when it grows up, or its general personality until that dog reaches around 18-24 months old. And don't forget the puppy energy level. If you get an adult dog, you can see the dog's general personality, and you can also see a mature version of him. Most adult dogs are very adaptable and most will adjust well to your home.
Adult dogs can and do bond to new owners quite readily.
In fact, German Shepherd Dogs want to bond to an owner strongly, and are very willing to do so to the first person who shows them love and caring. You still need to provide structure, love, and training for an adult dog, as you would for any dog you raise, but the puppyhood chores are over for the most part with most Rescue dogs. Which is super - you're already partway through adolescence in a 1 yr old dog.