Skip a couple of heats and no problems should arise. If you do not plan to breed to improve the Rott, then I would spay her. Many of us breeders are in it to save and improve the breed.

Not knowing her past you must start from the beginning with her training. She sounds to me like she doesn't take you or your daughter as her alpha.The best way is to make her work. For example, no treats or praise unless she earns it like sit, stay, ...