This recommendation comes from Chelsea. You can follow her on her blog The Globally Curious and on twitter @chelsea_mcgill4.
The Telling (2000) by Ursula K. Le Guin
"Once a culturally rich world, the planet Aka has been utterly
transformed by technology. Records of the past have been destroyed, and
citizens are strictly monitored. But an official observer from Earth
will discover a group of outcasts who still practice its lost
religion-the Telling. Intrigued by their beliefs, she joins them on a
sacred pilgrimage into the mountains...and into the dangerous terrain of
her own heart, mind, and soul."