From Longman Dictionary of Contemporary Englishin your dotagein your dotageOLD/NOT NEWin your old age → dotage
Examples from the Corpus
in your dotage• What Lord Denning's Spectator interview in his dotage had revealed was unguarded language.• Thurmond is as mean in his dotage as he was in his younger days.• Appearance and character Many portraits of Wordsworth and Coleridge exist, though unfortunately Dorothy was only painted in her dotage. 