Speaking as a former GSD Breeder and also as someone who works with a Rescue and our local Humane society, first let me caution you that many of the people who do the intake on shelter dogs and rescue dogs have very little knowledge on breeds or breed standards, and I know a few who will label a dog wrongly in a misguided effort to improve the dog's chances of adoption or to avoid breed restrictions at apartments.
If you could post a picture from the side it might help. Also how old is she in the picture? Weight?
At any rate she's beautiful and the bond that grows between you is more important than the breed.
My big guy Creed was labeled as a Chow/Golden mix. HA! Try Newf and Irish Setter! I was told they thought that since he has a dark spot on his tongue that was proof he was part Chow.
So just love your dog for who she is, always be there for her, and have a ball training!