Hi im over the age of 18 now and my father become a citizen when i was 12 years old but i never got a chance to apply for a green card my old lawyer really messed things up and then my dad passed away when i was 15 i was born in 1986 and there for was still under the age of 18 in 2001 so can i still apply for n600 and if yes what proof do i need to give or what are my other options thanks