There are a ton of temperament and genetic issues with our breed, and since it's a 12 + year commitment it's great you are doing your research on the breed ahead of time!
Do NOT go to a petstore and be careful of the Puppy Millers who lie on the internet and say they are 'small' breeders. Big issues with those pups and you pay a ton for them up front too.
Have you seen this site yet? --> Welcome to the GSD/FAQ's for the first time owner - German Shepherd Dog Forums
Specially this --> How to find a puppy!
and this ---> Different 'flavors' of German Shepherds
A GSD isn't necessarily a GSD as far as any specific type/look. Different colors and different shapes so we need to figure out which we prefer and then look for the breeder who is breeding to that type.
Kind of be aware that the way to show off a GSD in an official photo has their back leg extended which slants their back down to make them look lower. Many of these dogs, if standing upright with hind legs beneath them, stand more level.
Good luck and make sure you read all the links I posted. The more you know the more a good breeder will consider you for their pups and you will end up with the perfect healthy pup!