This comes from WorldConnect at Rootsweb.com:
Census: 27 JAN 1920 Brentville TS., Prince William Co., Virginia, Ancestry Pg. 24 - age 36
Census: 18 APR 1930 Brentville TS., Prince William Co., Virginia, Ancestry Pg. 23 - age 36
Her name in those censuses may have been Olla.