A 22-year-old female on antiepiletic therapy got married. When should the folic acid supplementation be advised to this female?

"The U.S.Public Health Service has recommended that all women of childbearing age and who are capable of becoming pregnant take 0.4mg of folic acid daily. If however, a pregnancy is planned in high-risk women(previously affected child), supplementation should be staed with 4mg (=4000 microgram) of folic acid daily, beginning 1 month before the time of the planned conception." Ref NELSON 19TH ED.