[APG Public List] Age 21 as legal mandate for sale of land in 1814 Virginia

[CL Swope (alfonsa)]

The date of birth of my target is said to be Jan 1793, and he is said 
the youngest of the sibling  group. His only brother died in the early 
1800s.
In April of 1814 the target and his four sisters advertised their 
inherited land (Virginia) for sale, and in May of that year sold it. By 
this time, my target was 'of Pennsylvania', but his siblings, and the 
land, were in Virginia.
I suspect the sibling group waited until 1814 to sell as he had just 
turned 21 and that  the  decision to sell at that time supports the  
reported (and so far unverifiable) birth year as well as his position as 
youngest in the sibling group.
Am I correct that there is a legal precedence for this assumption in the 
time frame? Google Books turns up quite a few references to court 
proceedings seeming to support my thought, but I'd like to be certain. I 
can think of no other reason the sibling group would have waited, and 
the coincidence of age seems a strong indicator to me. Am I in error?

Thanks in advance,
Cynthia Swope