Is Taking Folic Acid Tablets During Pregnancy Safe?

hi doctor im 30years i want to get pregnant and im taking 5mg folic acid pre day . is it right. .and i got twice miscarriage.but that time i did not take folic acid from before.and i was working that time as im a teacher.and my period r not every month please help me .what shoul i do right now.i want be a mum please