Each GSD puppy that I've had has always followed one of my other dogs through the dog door. Easy peasy. Well, if you have more than one dog, that is.
So barring that, I would get someone on each side of the door, and lift the flap half way up, and call her through. Back and forth, back and forth, big party on each end. Try not lifting the flap up as high after a while. If she won't go through it when it's all the way down, take your hand and just push on the bottom of the flap to show her that she can move it to make it open. She's a smart girl. She'll figure it out. I bought an 8 month old Italian Greyhound one time that was clueless, and ended up just shoving him several times out the dog door. He figured it out.
~ Diane in Okla
Carly ~ AKC Champion, GCh pointed, HIC
Sage ~ AKC Ch. pointed (13 pts - chasing that last major), HIC
Russell ~ the big boy
Mimi & Pi ~ the meezers