That is indeed her, though her name was Nancy Manassas Thomas.
Amanda Langston was her mother and John Langston and Clarissa Matthews (listed as Clarissa Langston in the 1870 census) were her grandparents. In 1860 her family (before she was born) was living next door to John and Clarissa and likely on John's land (he owned multiple pieces of land and at least one other son-in-law and family was living on the land, mentioned in his will, though William and Amanda were dead by the time he died).
Nancy lost both her parents and her maternal and paternal grandfathers by the age of 8-10 in 1870. Her sister is living with her with Clarisa, Angenet. One brother is living with her paternal grandmother in Kentucky (she lived in Georgia and moved there during that time) and another brother with her paternal aunt (who seemingly was childless herself so might have enjoyed having a child to raise).
She would marry my other ancestor, Elias Bryant. As it turns out he was basically orphaned (though not nearly as young, hard to beat 7 days) after his mother died when he was young, and before that his father (John P Bryant) ran off with another woman to Tennessee and started another family (as it turns out through DNA I've likely confirmed he was having children with a third woman, a widow next door, at the same time as his wife and his mistress/future second wife). Some stories suggested he died in the Civil War, though through research I discovered the truth (he was gone by 1860 in Tennessee so didn't take much to realize he didn't die in the war at least). I like to call them the married orphans. Probably why I have such little passed down information of either of their lines, or of William's service in the war.