I suppose there is a view that dying young is a sort of immortality.
I prefer the opposite approach. I think the phrase your never too old is a tad optimistic but some people are lucky or otherwise manage to carry on living life to the full as long as possible.
Here is a list of people who show they way:
Tom Baker - The Doctor Who actor - now 78, but has returned to recording Dr Who audio (radio/CD) adventures for Big Finish Productions. Still interesting in amusing in interviews - I love his quote - "I wish I was 70" "or even 75"
Dave Allen - The comedian - sadly died aged 68 - but retained a philosophical and humorous attitude to life until the end. He became an enthusiastic painter in later life. He was always looking forward and rarely allowed his shows to be repeated.
Harry "Buster" Merryfield - aka Uncle Albert in the long running TV show Only Fools and Horses - despite a long amateur involvement he only became an professional actor at 57. I liked his idea of a chat show where he proposed he would interview people over a few drinks in a bar - sadly this was never commissioned.
Humphrey Lyttelton - Chairman of the radio 4 programme I'm sorry I haven't a clue. Enough said for those who have listened to the programme.