What's the Name of That Book??? discussion

A young woman is part of an elite group of agents from an advanced civilization that are sent to primitive worlds to help keep them from destroying themselves. This is done in secrecy -- they cannot reveal their mission to the locals nor that they're from a more developed world. This young woman wants to go on a particular mission but is not allowed because it's too dangerous, so she stows away. Once there she ends up playing a central role which is interpreted by the locals as something of a sorcerer/goddess because of her powers that they do not understand. She and her team set up a fairy tale quest, with two of the local men having to prove their worth to receive special powers that will help them save their world. This involves lots of running through dark forests and being challenged by frightening creatures.

Could it be Enchantress from the Stars by Sylvia Engdahl?

Carmen Ferreiro-Esteban
Author of Two Moon Princess

That's it! Thank you so much!

You are welcome.
I loved that book as well.