Age is a relative thing . . .
I never realized how relative it was until I noticed how many senior citizens live in my high-rise apartment building. Lots of them, some well into their 90's.
When you get to hang out with older folks occasionally and find out that, someone who is, say, 70 years old has passed away, it's no longer thinking that someone old has died. Because, once again, it's all relative. When you see people around you who are 80 and 90 years old, 70 ceases to seem old. And as elders around you are saying, "Morty was only 70 and he died? But he was a young man," it begins to change your perspective.
A couple of generations ago, 40 was thought to be middle age. Today, 40 is young, and 50 is thought to be middle age. (Much of that has to do with the extended life span we have today compared with the same point in the last century.)
A lot of this is also impacted by advances in health care. When my dad was 40, he was diagnosed with angina pectoris, a very common heart condition. At the time, he was a dedicated tennis player, and his doctor told him he should no longer play tennis. With today's medications and advances is both diagnosis and treatment, if he were diagnosed at 40 now, the doctor would probably tell him to start playing tennis.
When my generation was 18, the common saying was, "Never trust anyone over 30." Then we all turned 30. Oooooooops! Well, y'know what? No big whoop.
Personally, the big jump I'm looking forward to is 50. I've got a while to go, but I occasionally read my dad's copy of Modern Maturity, the monthly magazine he gets from AARP and see all the coop people who are turning 50. (Ohmigod! Mick Jagger's over 50??? Yeah, well he does look kind of ancient. But then, he always did. :wg: ) Anyway, you can join AARP when you're 50, and I can't wait to present that l'il ol' AARP card somewhere for a discount and have someone say to me, "Hey, dude, you don't look that old." :D