I sent my N600 on November 2014 amd received a letter on January 2015 saying they received my application, they took almost a year after I heard back from them on December 19 , 2015 they send a request for evidence and get that letter 2 days later, I send the evidence they requested since my father died I was never under his custody but I derived USC when I was born, I'm 25 now and I have always have an USP but wanted to get the certificate just in case, March 7th they put me in the que for Oath ceremony and I have no heard from them since then, I call the National Center and was told to wait any time between 90 to 120 days after the email I received saying I was in the line for oath ceremony so in short
Nov 14, 2014 send N600
Jan 13, 2015 received a letter from USCIS
Dec 19, 2015 Request for evidence
Dec 21 ,2015 request for evidence letter received
Jan 5, 2016 sent evidence
March 7 , 2016 Oath ceremony que
June 8 , 2016 Infopass app.