But think of all the writers who are in their 80s

During my most recent time of thinking it would be a good idea to start writing again (ie now, it happens about biannually), I'm constantly reminded of this conversation from Cabin Pressure: 

DOUGLAS: Two things, Arthur: Australian accents aren’t genetic; and you can’t do one.
ARTHUR (still in the dreadful accent): Well, you’re entitled to your opinion, sport!
CAROLYN: Arthur!
ARTHUR (normal accent): Sorry. Also it’s good because it means I can play cricket for either England or Australia, whichever need me.
MARTIN: Can you play cricket?
ARTHUR: Don’t know. I’ve never tried.
DOUGLAS: Arthur, you’re almost thirty. Don’t you think you’re leaving it a little late to embark upon your career as an international sportsman?
ARTHUR: Not really. Shane Warne is forty-one.
MARTIN: Yes, but he’s retired. I mean, that’s like saying Geoffrey Boycott’s in his seventies.
ARTHUR: You see? Well there you are, then.
(Carolyn’s phone trills a text alert.)
CAROLYN: Ah-ha! Gordon’s finally finished. He’ll meet us in the office in half an hour.
ARTHUR: Oh no! I still haven’t got him anything!
CAROLYN: Arthur, you really don’t need to …
ARTHUR (running off): Yeah, I’ll meet you there!