Joel Grey was born in 1932 and created the role in 1966; Cumming was born in 1965 and 1st played the Emcee in 1993. He's traditionally perceived to be "ageless," approximately mid-30s. When Cumming returned, pushing 50, he was a considerably older character, and that offered a wry take with added poignancy.
Have never considered this character's age, and wonder how it impacts the story, if at all. Arguably, in the iteration with the Mendes coda, the tragedy is horrific no matter how old he is. Yet a young man in effect coming out via this club gig is an interesting if inadvertent slant. Just beginning his adult life, snuffed out.