Legend has it that Dante had the vision that gave rise to "The Divine Comedy" on his 35th birthday, a milestone he called "the middle of the journey." Here I am, a few weeks short of a similar passage, sitting in front of a computer terminal musing about what Tom Lehrer, then 37, said about Mozart: "It's sobering to realize that when Mozart was my age, he had been dead for two years."

Thirty-five is supposed to be halfway to the biblical three score and 10, but for Mozart it was the end of the line. No matter. What gnaws at me is that when Tom Lehrer was my age, he was already a professor at Harvard and a cult figure on the cabaret circuit.

I am one of about 10,000 aging baby boomers who were born in America on Feb. 16, 1947. Not a big group to compete with, about as many people as live in the thriving metropolis of Ferndale, Md. But one of those who goes through life writing 2-16-47 on official forms is Terry Crowley, a sometime pinch hitter for the Baltimore Orioles. Is there justice in a world that allows Crowley to make it to the big leagues, but doesn't even give me a chance to hit .218 in the low minors?

Recently, at a very Washington dinner party, someone suggested that instead of horoscopes, we should all be identified by the presidents whose terms we were born under. That would make me a Truman with Tom Dewey rising. I can just picture what Sydney Omarr would write on my birthday under this new system: "You're a no-nonsense guy with a salty tongue who likes long walks and can endure extremely warm kitchens. You wear a hat, got your current job by accident and have an unrealistic opinion of your daughter's musical talents. Avoid deep freezes, the color pink and generals with messiah complexes."

Cataloguing people by their presidential signs has a certain logic. Ronald Reagan, after all, is a Taft. Our attitudes and beliefs are shaped, far more than we'd like to admit, by the era in which we live. The 1950s taught me to take middle-class comfort for granted, the '60s alerted me to the moral bankruptcy of bourgeois society and the '70s implanted the notion that all-cotton shirts are superior to polyester blends.

One parable tells it all. During my years as an angry young man in the late 1960s, I dreamed of having just one hour in the White House to tell the people in power exactly what was wrong with this corrupt, militaristic country. By the time I actually got to work in the White House in the late '70s, my political beliefs were about as bland and as noncontroversial as a television editorial and I wasn't even so sure I was right about them.

No wonder I am entering my mature, adult, take-charge years devoid of any firm convictions, still groping for a set of values a little more definitive than the credo: "Try to be a good person because, who knows, there just might be a God. Anyway, you'll sleep better at night without having to worry about the IRS, the FBI or lipstick on your collar."

Take, for example, my love-hate relationship with materialism. There are weeks when I define myself exclusively by things I don't consume. It's like having your epitaph read: "Despite the best efforts of Madison Avenue, he never bought a house, a new car, a color television set, a home computer, a pair of cowboy boots or a quilted ski jacket."

Just when I am waxing particularly pious about my Gandhian sense of self-denial, I look around the apartment in the raffish, but trendy, Adams-Morgan section of Washington and all I see are cliches. In the kitchen are the newly acquired Cuisinart and imported pasta-maker. Hanging on the dining room wall is the stereotypical Saul Steinberg New Yorker poster. The living room features a sofa from Scan with butcher-block sides, and there on the chrome-and-glass coffee table is the latest issue of Consumer Reports. It's as though I picked up all my ideas of modern living by reading "Doonesbury."

Even my worries are about as distinctive as the architecture of a suburban shopping mall. Until we got married 18 months ago, my wife and I spent every spare hour agonizing about our relationship. Now that the marriage is secure, we put the same amount of emotional energy into brooding about our respective careers. I'd venture a guess that 10 years from now we'll be lying awake nights fretting over whether our putative child will get into the nursery school of his or her choice.

These days, free will extends about as far as choosing among seven competing brands of pizza in the freezer at the local Safeway. Even without the benefit of reading Gail Sheehy, I know what the future has in store for me.

One crisis point will be when I develop an intense craving for a red sports car and an inappropriate crush on a 17- year-old Swedish au pair girl. If we have progeny, another benchmark will be the moment I realize that no matter what I do as a parent, my child will spend his adolescence hating me for it. It is also foreordained that I will never speak flawless French, finish The Magic Mountain by Thomas Mann, master the commodities market, go on tour with a rock group or emerge bloodied but triumphant from a barroom brawl.

Recently, reading a novel about the 1940s, I was overcome with regret that I was born too late for World War II. How ghastly to be caught up in someone else's nostalgia for total war. But I suspect my cravings for a grand adventure will increase as I age. After all, how many times can you retell the story of the night we took the administration building?