If you had your green card before you turned 18 years old and resided with your mother at the time, you automatically became a U.S. citizen by law under the Child Citizenship Act of 2000. In order to get proof of your citizenship, you can apply for your U.S. Passport with the Department of State or you can apply for a certificate of citizenship with the Department of Homeland Security.
Answered on Jul 31st, 2013 at 10:26 AM