WARNING: this will be an un-fun, thinky post.
I've been thinking a lot this weekend about age - which is funny, because in general I don't. At all.
On the one hand, I've learned things about people older than me which suddenly and momentarily made me feel the full gap in our ages. C.S. Lewis wrote about a woman who measured age in experience; whenever she learned something new about the world, she would say that she had been made older. So, when I learn of something, you know, intensely grown-up about someone (say, they've got a kid, or they're having a house built to their specifications), it's as if, in my mind, they've been made older by the revelation. (However, learning these things also teaches me that you can be the kind of person who has a kid or builds a house, and you can still be the same person who has the ability to befriend li'l me; in other words, I am "made older" as well. But still, I feel much younger than the person with the experience.)
On the other hand, I tried to clean out my closet at my parents', which made me feel as though I've lived forever (or that I'm a hopeless packrat). Look at all these years upon interminable years, straining against the white-painted wooden doors, threatening to break them with the sheer mass of stored, forgotten stuff, the very chaff of my living! (Perhaps I should have added "overblown prose" to the warning at the top.) It seems obvious to say that I'm the oldest I've ever been, but sifting through the papers and clothes and cassette tapes and hand-glazed ceramic ducks of my youth made me feel it. (Even the tennis racket from the abortive attempt at gym class senior year in college is already more than two years old.)
All this thinking has served to convince me of what I already knew: that age means pretty much jack.