Individual Details

Jane is probably the young lady, age 16-26, in the 1820 census with her parents. Her father left her most of his estate with her mother's one third to inherit after the death of her mother Agnes.
Apparently the mother died soon after Isaac:
Deed Book O page 87 Jane R. Lawson for $1.00 sold Isaac Lawson Jr. the tract of land on which their father, Isaac Lawson, Sr. resided; it had been willed to her by her father. 215 acres on Kerr's Creek Adjoining lands of James Lackey and John Simonds heirs. He took it subject to the payment of all the debts of Isaac Lawson Sr. Deceased for which it is legally bound by deeds of trust on otherwise. Recorded May 3, 1824 [day made]

Her mother Agnes was still living when her dower was laid off:
At Rockbridge County court February 4th 1822 This report of the commissioners appointed to assign Agnes Lawson her Dower in the lands of Isaac Lawson decd being returned was ordered to be recorded. Teste.

Father	Isaac Lawson ( - 1821)
Mother	Agnes "Nancy" [surname unknown] ( - 1823)
Sibling	ROBERT Lawson Jr (1776 - 1850)
Sibling	Isabella Lawson (1780 - )
Sibling	Elizabeth Lawson ( - )
Sibling	David Lawson (1785 - )
Sibling	Agnes "Nancy" Lawson ( - )
Sibling	Isaac Lawson (1789 - )
Sibling	James Lawson (1790 - )
Sibling	Rebecca Lawson ( - )
Sibling	Andrew K. Lawson (1795 - )