Three birthday parties were quietly celebrated at Paul Young's restaurant last night, and everyone had a wonderful time:

Yolanda Ruiz from El Paso, Texas, who would not give her age but admitted to being born in 1933; Louise Carpenter, observing his 55th, and Jimmy Carter -- also observing his 55th -- who came from down the street along with his wife to sip some white wine and dine with a couple of old friends.

"I will never forget this birthday as long as I live," Ruiz said. "He blew me a kiss from across the room. He's a Libra; we fellow Libra's get along." Happy with food, wine and good company and dressed in a red party dress, she said, "I can't believe I shared a birthday with the president."

Although two days late (the president's birthday was Oct. 1), the Carters relaxed with old friends from Atlanta, Ambassador to Australia Philip H. Alston and his wife, Elkin.

In a very crowded room, they were left alone by fellow diners except for one man in a plaid jacket who ventured over to shake hands and pat the president on the back and returned later with his girlfriend.

People at surrounding tables showed remarkable restraint, almost to the point of ignoring the Carters.

As one man explained, "Sure we know he's the president, but they deserve an evening out the same as anyone."

The president, wearing reading glasses, scanned the menu and chose a tossed salad with blue cheese dressing, rainbow trout, asparagus and fried onion rings. The first lady, wearing dark, horned-rimmed glasses, selected the duck with orange sauce and asparagus.

Like any couple out for the night, they treated the other diners asneighbors. Mrs. Carter crossed the room to shake hands with Ruiz, wishing her happy birthday, then went to the Carpenter table.

The head waiter, Emanuel Ahigustiades, offered the president a small cake with a candle. Looking embarrassed, Carter motioned for him to take it away.

Rosalynn, in a mischievous way, began softly singing, "Happy birthday to you." A couple of hovering waiters joined in, and the dining room swelled to a crescendo of "Dear president, happy birthday to you."

The room settled down again and the president licked a bit of frosting from his fingers as he cut a small slice of cake and handed it to his wife.

There was no politics as the president shook a few hands at the tables next to his, talked briefly to a photographer about a meeting long ago, exchanged a submarine memory and slowly left the room. It was a brief two hours, and they were just another couple who had a nice evening in their neighborhood restaurant and were going home.