A couple of weeks ago, I was having dinner with a friend of mine who had recently celebrated her 29th birthday. She wasn't very happy about it: it seemed her 30th birthday felt like a deadline, a looming reminder of everything she had yet to accomplish -- and she felt, I suppose, like time was running out.

I'm in my mid-forties, and I have to admit that I was a bit stunned that she was so keenly feeling the passage of time. Good Lord, I remember thinking to myself. At 30, I was only just beginning to feel like a grownup. And in truth, my 30s were awesome. It was a decade of all sorts of adventure: international travel, international residence, relationships (marriage, motherhood), huge career shifts. I feel like I did most of my growing up in my 30s. "Oh, honey," I said to my friend, "the truth is you've only just begun. You've finally approached adulthood -- and you've got so many more adulthoods ahead of you."

I admit that I felt a bit wistful as I said it: after all, in my current state of mind, "mid-40s" means "middle aged." And they don't call it "middle aged" because you're young and dewy anymore, a nagging voice in the back of my mind insisted. She's young, but time is running out for you.

On a recent flight, I tucked into a new book, Dancing Fish and Ammonites, by Penelope Lively. It's a memoir, written by the author at 80-years-old, and includes her considered thoughts on aging. I'm about 3/4 of the way through (and it has been delicious all the way), but this particular passage, written at near the beginning of the book, turned me inside out:

Years ago, I heard Anthony Burgess speak at the Edinburgh Book Festival. He was impressive in that he spoke for an hour without a single note, fluent and coherent. But of the content of his talk, all I remember are his opening words: 'For me, death is already sounding its high C.' This was around 1980, I think, so he was in his early sixties at the time, and died in 1993. I was in my late forties, and he seemed to me -- not old, exactly, but getting on a bit. Today, people in their sixties seem -- not young, just nicely mature. Old age is in the eye of the beholder. I am eighty, so I am old, no question.

And then later in the book, as she talks about her life in the 1990s, she says this:

We are into the 1990s here, and I have hit sixty. I don't remember feeling especially bothered about this -- full of energy still, writing, living. The view from eighty says: huh! a mere slip of a girl -- just you wait.

I love that her view from 80 considers 60 to be "a mere slip of a girl." I love that she considers 60 to be simply "nicely mature."

Age, it appears, ain't nothin' but perspective.

And now, after reading this book, it seems I've only just begun, too.