R. A. Lafferty 
Aurelia 

Aurelia was a fifteen-year-old girl from a very advanced world. She’d passed Starship building easily enough, but she’d slept through most of celestial navigation. That was how she ended up on a little back-water dump like Earth, where her advanced powers seemed like miracles. Some thought she was the Messiah. Some thought she was the Devil. No one was prepared for the truth.