Place of Origin:
Engines of War
Stephanie was a human colonist on the planet Moldox during the Last Great Time War. She had hair the colour of a raven. She survived the initial stages of the Dalek occupation of Moldox and became a resistance fighter. She fell in love with another resistance fighter known as Cinder and it was with Stephanie that Cinder had her first kiss.
Cinder rewatched the memory of her first kiss with Stephanie when Karlax and the Castellan used the Time Lord mind probe on her on Gallifrey. (Engines of War)
BEHIND THE SCENES
George Mann stated that by revealing Stephanie and Cinder had kissed, it was his intention was for Cinder to be a lesbian.