The reporter was young and inexperienced, and asking one of those squirmy questions young reporters are famous for.

The candidate's wife responded with a look of mock horror, then turned helpful and smiling.

"I thought everyone knew how old I was," said Joan Kennedy. "Forty-three."

Standing there beside her husband yesterday in her debut campaign performance, Joan Kennedy met the press -- pleasantly, cooperatively.

She sat on a bale of hay at her grandmother's ranch near Gainesville, Fla., for photographers, paraded through the glare of TV lights and held the roses proffered by one audience as she listened to her husband's every word.

This is a presidential campaign for the first year of a new decade, but the candidates seem, more than ever, to be pushing the time-honored, traditional use of the wife and family -- everyone from octogenarian mothers to teenage sons and daughters. And this is a political year when wives have a special meaning -- a year when an ambitious and vocal first lady gets cheers and boos from audiences who alternately see her as the great helpmate or the unsalaried meddler. And for Joan Kennedy, yesterday's performance was a special hurdle that took on special significance.

For years she had been less than thrilled at the thought of her husband running for the presidency. And now that she's joined him in his quest, she is being thrown once more into the public world she has so carefully shielded herself from these past two years.She has lived apart from the Washington scene since 1978, studying music in Boston, speaking out and facing up to her problem with alcoholism and her struggle to regain her self-confidence. The speculation was that Sen. Edward M. Kennedy would not -- could not -- run successfully without her. Last week Joan Kennedy, in a small press conference that quietly eased her into the limelight again, emphasized that it was her decision to campaign.

The easing in is still going on. There are no speeches this time around. There were no public greetings when she and her husband, who had flown in from Chicago, met for the first time in her grandmother's simple white frame farmhouse. President Carter has his Miss Lillian and Sen. Kennedy his mother Rose; Joan Kennedy has 81-year-old Andasia Bennett.

Mrs. Bennett led everyone in prayer before they sat down to a barbecue of ribs and pecan pie under oaks dripping with Spanish moss, then generally took charge, marshalling her granddaughter, the senator, the press and a platoon of Secret Service around the farm.

Joan Kennedy wore gray slacks, red turtleneck and a checkered derby hat and often held her grandmother's hand. She and the senator toured the farm in an obvious display of togetherness for the truckloads of reporters and cameramen who trailed the couple as they raced around the farm.

Joan Kennedy said she had been coming to the farm "since I was a baby. We used to play with the chickens." She was then asked how you play with a chicken. "You squeeze them until you drop an egg," she replied, adding that her grandfather used to pay 10 cents per dropped egg.

That was the tone of the afternoon as the senator and Mrs. Kennedy looked raptly at bales of hay and conveyors and asked how much the machinery cost and how much the hay sold for -- all the while as the photographers took pictures.

Joan Kennedy's grandmother had invited a few local guests to the family barbecue and most seemed to take a visit from Sen. Kennedy in stride Luther Honey, a car dealer who brought over some vans for the press, was asked why the sheriff and a half dozen of his staff would be there and he said. "Oh there ain't nothing else to do and they're getting a day's pay and a free lunch. What else could a sheriff want?" As he looked across at the senator and Mrs. Kennedy he said that their separation "is okay with modern people but that has got to hurt him to an extent with other people."

Later, on the plane headed for Miami, Joan Kennedy switched into a red two-piece dress and black high heels for a fund-raising dinner, then came back to chat with members of the press. She seemed nervous but determined to stick it out and chatted about her studies and family animatedly as her freckle-faced 12-year-old son Patrick raced through the plane. The reporters did not press her for an interview; in a show of respect in a way, they steered from asking her any serious questions about her life.

Joan Kennedy said, "When I saw him on this trip I though 'Oh, you again,'" explaining that as a mother she was worried that he was missing too much school. But "His teacher said this was more of an education," she said.

Asked what her children thought of the campaign, she said, "Well, they liked my press conference." She was referring to last week's session with four reporters in Boston. "It was good -- for starters," she said with a grin.

Politics leaves her little privacy -- at least from the public who seem to have endless opinions about the private lives of the Kennedys. One woman in Chicago listening to her husband's speech the day before said that Joan Kennedy getting into the campaign is "just show biz, honey. It's all an act." That sort of absolute certainty comes from many women in the audiences these days.

In the Miami crowd listening as Kennedy railed against the president's inflation policies at a clothing convention, one observer said. "She's a lovely lady -- but I wouldn't want her job for all the tea in China." Still another said that her problems were "very sad but I think it's interesting that she's standing beside him."

for now, at least that outside world of comment and criticism seems not to faze Joan Kennedy. The smile was broad and genuine as she received a standing ovation from the 900 salesmen and saleswomen in the crowd, then moved on into the evening, watching her husband as he shook hundreds of hands, then pushed with him up to the platform for yet another speech before yet another crowd.