A balancing rule is, that older characters earn less experience, and therefor younger learn faster by adventure.
Anyway, Traveller was unusual in that it used age in a slightly meaningful way, but it definitely got away from the trope of all PCs being young and/or inexperienced.
Anyway, Traveller is the least futuristic science fiction setting ever (maybe). In game mechanic terms you have to start rolling for age-related characteristic effects starting at age 34 - you could lose strength, dexterity or endurance. At older ages you could lose intelligence too. But overall it assumes human lifespans more or less like they are today.
I think at imperial tech level's life extending drugs where not uncommon for the well off - depends on how you build the traveller universe.
And Tl:9 of course offers the first future techs, e.g. fusion reactors. Tl:A reliable interstellar travel and automatic factories, and huge progress in the high times of big trade empires spanning years of FTL travel, and the collapse of civilization, technology and dark ages, when ever those empires fall.
Living at Tl:F and being wealthy could buy you a lot of years, before you need to worry about age. But I was restricting my idea of a "better" assignment to Tl:8. So you can imagine every career path here and now, e.g. odd ones you never want to live in real life like the doctor who works for crime syndicate (above example), but that is fun in a role playing game, or would make a good trope in a novel or film.