Teacher 8, please come in

Teacher 8 - I'm currently preparing my upcoming N400 interview.  For selective service registration, since I had exceeded the age 26 when I first received my GC in 2010 (I was in legal non-immigrate status prior to 2010), I didn't need to register the service, correct?  In case that the IO asked me for evidence during the interview, do I just tell him I was over 26 when I received my GC?  thanks!