"I remember the last time you wrote to me asking to check on her, the daughter of an ordinary farming family from Lotus Village of the Gu Family, chosen by the people of Xuanzong because she was a girl of the Four Pillars Pure Yin. The people Xuanzong picks don't care about the other person's background; it should have nothing to do with her real identity.
As for the Gu Family... the Gu Family has been farmers in this village for generations, nothing special about them. The only thing special is that her maternal Lin Family produced a Top Scholar more than ten years ago, just when the new emperor ascended the throne and was cultivating his power everywhere. This Lin Qinghe was indeed fortunate, just happened to be chosen. He is now a First Rank Great Scholar in the imperial court; it's not impossible that someone might be targeting him because of this.