About Marriage Law

Dear Sir, My name is Rahim. I am planning to marry on 2020 Jan 10. I need a legal advice from you. According to Indian law, If the qirl wants to marry on 2020 in the month of January . In which year she should be born. What should be her date of birth. Her actual DOB is August 7 2002. Is she eligible to get marry on 2020 January. As per her marriage date, Could you please let me know the exact Date Of Birth . So that we can avoid child marriage. Thanks, Rahim