It's a toss up you'll find his age in Confederate Army records.

I did an Ancestry.com search and came up with this fellow, could be him.

1860 United States Federal Census about James Usary

Name: James Usary
Age in 1860: 22
Birth Year: abt 1838
Birthplace: Cherokee Nation
Home in 1860: Tahlequah District, Indian Lands, Arkansas
Gender: Male
Post Office: Tahlequah
Value of real estate: View image
Household Members:
Name Age
James Usary 22 Farmer

Lived adjacent to William Usary, age 55, Farmer, born in Tennessee