I turned 70 the other day. Ronald Reagan won't make it until Feb. 6, 17 days after he becomes the 39th president of the United States. (He'll be the 40th only if you count Grover Cleveland twice.)

Back in late 1910 and early 1911 when we were born, William Howard Taft was in the White House.The life expectancy then for white male babies was around 50 years, give or take a few months. So you might say we've both considerably beaten the rap, or the reaper. As of now, the National Center for Health Statistics says, both of us should be good for another 11 years plus, assuming we're average. That would get him safely past two terms in the White House; it would get me safely into the 20th year of retirement from daily journalism.

In addition to suffering from chronic hay fever, Reagan, so his doctors say, has a degenerative disease of the joints known as osteoarthritis that has caused a thumb to go numb. It's the osteoarthritis in my little fingers that hurts when I hit the far-left and far-right keys on my old Royal standard. Reagan's blood pressure reading is 130 over 80, lower than mine but I compensate with a couple of pills a day. On the other hand, he's had a prostate operation but I haven't. He keeps fit by riding, chopping wood and swimming; I swim.

The reason I venture into this medical intimacy is that I have been rereading Cicero's essay on old age, De Senectute (but this time in English, so thoroughly has Latin escaped me). Cicero cited as number two among the reasons "why old age is regarded as unhappy" the fact that "it impairs physical vigor."

"Age breeds aches," someone else wrote, and how true. Your medicine chest gets fuller and fuller; more and more of those barbarous television ads for sundry pills and potions jump out at those of us near, at or past the biblical "three score and ten" said to be "the days of our years."

Cicero, however, was a wise man; he listed impaired vigor only as enemy number two. His number one enemy was, and I think remains, that "old age withdraws us from active employments." But does it have to be so?

No, reasoned Cicero (who, by the way, wrote this at 62 and was beheaded at 63). "Large affairs," he said, "are not performed by muscle, speed, nimbleness, but by reflection, character, judgment. In age, these qualities are not diminished but augmented." Whether the presidency truly is an occupation for old age, we shall just have to wait and see. It is true that Churchill, De Gaulle and Adenauer all led democracies well into old age, but it also is true that their latter years were far from their best.

Like them, Reagan may prove some kind of exception. But most of the rest of us over 70 like to sleep a little later (don't call me before 10), read the papers more leisurely (a day late doesn't matter), sit further forward in the theater (but no ear horns like grandpa). We also become wary of the obituary page yet often feel a compulsion to turn to it first. A while back, after sitting next to a friend at the third funeral in a row, he turned to say; "This has got to stop." But it won't.

Most of all, I agree with Cicero that reflection and judgment, if not character, are indeed augmented by age. Maybe that's why I don't look upon a Reagan presidency in a state of tremor, why I am more interested in what his election means in, and what effect it may have on, the sweep of our history. Time does extend judgment, or at least offer perspective.

When you remember first coming to Washington in Wilson's era and seeing his vice president sitting in the Willard Hotel lobby puffing a cigar; when you can still feel the pat of Harding's hand on your head; when you remember trying to interview Coolidge at college; when you attended Hoover's inauguration; when you vividly recall, as a cub reporter in 1933, joining the crowd in the Oval Office for your first FDR press conference (and press conferences thereafter from Truman through Nixon); when you used to be able to find your way through the Capitol catacombs; when you remember Cordell Hull and his State Department in today's Executive Office Building -- all such memories tend to put today's storms and crises into some perspective.

It is true, however, that age also brings impatience and expletives deleted on reading in this newspaper and others such verbal barbarisms as "the chief justice of the Supreme Court" or such historical garbage as "Washington was a sleepy Southern town until Kennedy's presidency" (it was FDR who woke it up). But such annoyances are the trivia of life.

What's important are human survival, the human condition and the American dream. Oh, I know that old men dream dreams and send young men off to war and that Reagan has been dreaming of good old days that never were, except for a lucky handful. But I also have concluded that age was an asset to our up-to-now oldest president, Dwight Eisenhower (a more 98 days past 70 when he left the White House). In making the judgments that produced the first break in the Cold War, Ike reflected upon the hot war in which he had played such a major role. We can only hope that Reagan, who reminded us many times during the campaign that "I have lived through four wars," will reflect upon them in setting new military and diplomatic policies.

We are conditioned by our past; I certainly was by tramping through Hirshima and Nagasaki some three months after the bombs had fallen. That didn't make me a no-nukes peacenik, however. It made me a believer in a balance of power tempered by arms control and disarmament, the only reality I can see in this world of adversity and adversaries. These are the issues I've followed and written about over the years and they are the issues about which I intend to write in judging the Reagan era.

But first of all, and fast, he must gain control of the economy so as to grind down the inflation that is especially cruel and damaging to the old.

The old. It has a terrible sound and conjures up for the younger and the young an unpleasant, often terrifying, image. (I had to explain to my dentist that we didn't always have social security and medicare, that there was something in America known as the county poorhouse -- "Over the Hill to the Poorhouse" -- of which he had never heard.) "Senior citizen" at least has a touch of dignity, and, besides, it sometimes saves you 10 percent.

So, to the president-elect I say: Do the job well, Ronnie, for all our sakes but especialy for the honor of your fellow septuagenarians.