I'm a permanent resident who immigrated to the US at age 6. Both my parents became US citizens in my teens before 2001 and 18th B-day. I am now in my 30s. I've been a permanent resident for over 20 years and am ready to become a citizen. I've spoke to USCIS customer representatives (on the phone) who insist that I file a N-400. OTOH some immigration experts state that I can tag onto my parents' citizenship so I should file a N-600 (I believe a simpler, less expensive and time-consuming process). What should I do (file a N-600 or N-400)? Please help me! Thanks in advance!