Miller was born, Marie Graciela Miller, on April 9, 1989, in Dallas, Texas, to Joseph and Roxanne Miller ("née", Polk), and she grew up for the first nine years of her life in California before finally relocating to the Shenandoah Valley area of Virginia, around the town of Washington, Virginia more precisely Huntly, Virginia, while she began singing at the age of 7. She is the third of 10 children. Miller was reared in the Roman Catholic faith at St. Peter Mission in Washington, Virginia. She grew up an avid reader and was inspired as a songwriter by the works of Fyodor Dostoyevsky, Leo Tolstoy, C. S. Lewis, and J. R. R. Tolkien. At the age of 12 she joined her family band, playing festivals and trading off lead and harmony vocals in duets with her sister.