Unit, the wisest thing to do would be to register for Selective Service System since you are under 25. It is very important if you are applying for US Citizenship and if you are a male between 18 to 25. The best part is that registering for SSS will not cost a penny. You can do it online through https://www4.sss.gov/regver/register1.asp or send a mail registration form which available at any USPS office. Does anyone know what is the earliest date to apply for US Citizenship? I heard that you can start the paperwork when you have completed 4 years and 9 months as Permanent Resident. By Nov 2006, it will be my five years of permanent residence in the US.