Prime of one’s life (6)
I believe the answer is:
heyday
(Other definitions for heyday that I've seen before include "One's peak period" , "Peak or prime" , "Period of greatest vigour" , "Period of one's greatest success" , "Boom time" .)
I believe the answer is:
heyday
(Other definitions for heyday that I've seen before include "One's peak period" , "Peak or prime" , "Period of greatest vigour" , "Period of one's greatest success" , "Boom time" .)