I now know that it means the age at which one shouldn't be getting none

That double negative is throwing me a curve but I presume you are speaking for yourself?

I should have put the double negative in quotes to point out I knew it was a colloquialism. Heaven forfend that any of the board members think I speak that way as a matter of course. I am over half way between my nonage and dotage or my two nonages by the above definition.!
Rod