Yeah, there is smth special about these 18 and 21... in my country, you are considered to be adult when 18, when you can vote, but there is still the age 21, when you are legally allowed to use alchohol...
I read an interesting thing about the age. Actually there are 3 ways to measure your age- biological, because human bodies are quite different, there are healthier people and not so healthy ones,so the aging process is different; the other age is so called historical, in other words- your birth date, it is fixed solidly, after all; and the third age is psychological, that's why some people act childishly longer than the others.... Hmm, I should tell you, I have also met a lot of young "old" people, I mean, too serious, too tired, too "all the games are stupid" people.
Whatever, you can chose your age!!!! sounds unbelievable? It is not. In a sensible way, of course. But you can really consider yourselves old at the age of 30, and you can say, you are young at the age ... whatever the age. It's how you see the life, is it an adventure for you, or only a hard duty??? you decide!!!
And a simply recipy for staying young longer- learn. Learn new things all your life. Sport makes your body fit, learning makes your mind fit, the result is marvelous. Just try