I have recently got my immigrant visa through my permanent resident wife and hence have made my travel plan to enter into & start staying in US in March 2013. As I know, to become eligible for naturalization, for a green card holder it takes 3 yrs if spouse is already a US citizen whereas 5 yrs if spouse is a green card holder. My wife is going to be eligible to get US citizenship in September 2013 after her 5 yrs completion as a PR. In this case, how long should I wait to apply for citizenship - 3.5 yrs ( till September 2016 as my wife is expected to be citizen in September 2013) OR the whole 5 yrs (till March 2018)? If still should it take 5 yrs for me in such case, then I will shift my travel date from March to September 2013. Asking for your advice please.