I need this information as well

To qualify for citizenship, generally applicants must demonstrate they have continuously resided in the United States for at least 5 years before submitting Form N-400, Application for Naturalization. This means you must be residing exclusively in the United States – not in any other country

The general rule is that you must have five years of continuous (unbroken) residence in the United States right before applying for naturalized U.S. citizenship 

It took me 6 months, could take you 12, all depends on documents and etc

I agree with @Sandra, I also wanted to know more about this in general