The adult censuses imply a birthdate in 1842, but she was recorded in the 1850 census as age 11, with enough younger siblings that compressing them all to be born in the 1840’s would make the spacing too tight. So she was probably really born no later than 1840.

1870 census of Menifee Co., Ky, Dry Ridge precinct, Rock House P.O., enumerated 6 July, lists on p. 12 as family #78:
Brown, Moses, 36, farmer, b. Va; Nancy, 29, b. Va; Green, 8, b. Va; Mary, 6, b. Va; John, 5, b. Ky; Louisa, 5/12, b. Feb, Ky.

1880 census of Menifee Co., Ky, Ridge precinct, enumerated 11 June, lists on p. 30 as family #246/263:
Brown, Morge, 47, laborer, b. Va Va Va; Nancy, 38, wife, b. Va Va Va; Greenberrie, 19, son; Elizabeth, 16, dau; John M., 14, son; Beckie, 10, dau; Rosa, 8, dau; Boon, 5, son; William, 3, son. All children born Ky Va Va.

1900 census of Rowan Co., Ky, Pine Grove precinct, enumerated 8 June, lists on p. 6B as family #104:
Brown, Morgan, 65, b. May 1835, Va Ireland Va, farmer; Nancy, wife, 58, b. Jan 1842, Va Ireland Va; Wm, son, 22, b. Dec 1877, Ky Va Va; George, son, 19, b. Nov 1880, Ky Va Va; Branum, Jos L., grandson, 11, b. June 1888, Ky Ky Ky.