Found this record 1870

Name: Sarah Fallin
Estimated birth year: abt 1854
Age in 1870: 16
Birthplace: Virginia
Home in 1870: White Chapel, Lancaster, Virginia

Race: Black
Gender: Female
Post Office: Lancaster

she is living with a family named Jessup.

Do not see her listed as a FPOC in 1860 either.

Suggest you post in surnames forum - to get records after 1865 in order, then after you have consolidated what can be found (birth, marriage, death, siblings) you can begin to tackle slave research.

Denise