Read puppy section. She's not aggressive. Opinionated, maybe. Aggressive, not likely. Is she your first GSD puppy?
By keeping her in the crate except to potty, eat and exercise, she's not getting what she needs from you to grow mentally. She needs time with you, training can begin, socialization to sights, sounds, smells, etc. She needs to be able to bond with you. Look into flirt poles.
A tired puppy is a good puppy.