Is she a longcoat? Even then I would hesitate to shave a GSD. As humans, we think of their fur as a hot winter jacket so makes sense to remove it in the summer.
But reality is a dogs fur coat is NOT the same and it actually will INSULATE them from the heat. So when we shave it off it makes it harder for them to regulate their temperatures to stay cool. Different for dogs with 'hair' like a poodle and that will grow forever.
Heat Wave! Should You Shave Your Pet? | ASPCA
Why you should NOT shave your Dog for Summer | It's the Dogs Life
Thinking About Shaving Your Dogs Hair Coat For The Summer? Think Again.