When I became a Permanent Resident, I was supposed to register for the Selective Service. However, I was not aware of this requirement and therefore did not register before I aged out. Can I still file an application for citizenship?

If you did not register because you were unaware of the requirement, or were made aware after you passed the age to register, you can submit an affidavit along with your application explaining the reason why you did not. You should also obtain a Status Information Letter from the Selective Service stating that you are over the age and are no longer required to register. You can do so by calling their hotline or filling out the application on the Selective Service System website.