Ronald Reagan celebrated his 69th birthday many times over today during a barn-storming tour of New Hampshire during which he agreed to debate his GOP opponents, visited a George Bush headquarters and knocked a plaster moose head off a wall in a Kingston coffee shop.

Reagan was reminded of his age at the first stop of the day when a girl at Timberlane High School in Plaistow wished him happy birthday and then added, "Are you too old to be president?"

"I don't think the number of years are very important as long as you retain your faculties, your physical abilities and so forth, and I think I have," Reagan answered, adding that he thought his experience would be beneficial in the White House.

At Raymond High School, in Northwood, Reagan answered the question in a different way. Asked how he felt about his age, he responsed:

"All I can say is that, compared to the alternative, I'm very happy."

Almost everywhere Reagan went there were birthday cakes, youthful choruses of "Happy Birthday" and reminders that he is not as young as he used to be.

On occasion, in the noisy melee of crowds and traveling press, Reagan had trouble hearing questions from the audience.

During a flight from Los Angeles to Boston on Monday, the former California governor explained that this was not a hearing los caused by age, but instead was the product of a movie accident 40 years ago.

"I was doing a shoot-'em-up movie back when I was the Errol Flynn of the Bs," Reagan said. "An actor put a .38 up to my ear and fired it."

Reagan said he was knocked off his feet by the force of the concussion from the blank cartridge and suffered a minor impairment of hearing in his right ear.

Reagan's long day in New Hampshire ended with a gala birthday celebration at a Chinese restaurant in Holoksett attended by 225 well-wishers and more than 50 members of the media. Reagan, who was born Feb. 6, 1911, in Tampico, Ill., was presented with a white cake decorated with three red-and-blue candles and was given a wooden elephant coat rack, with the trunck up for luck, and a container of jellybeans, one of his favorite foods.

Before blowing out the candles. Reagan said that each one of them represented 10 years of his life and that he was celebrating "the 30th anniversary of my 39th birthday."

Today's campaigning in New Hampshire marked a sharp departure from the leisurely, set-speech style that Reagan had followed until his loss to Bush in the Jan. 21 Iowa caucuses.

Reagan made nine stops today, shaking hands and answering questions at most of them. Often, he was in crowded quarters. At Papa's Coffee Shop in Kingston, he accidentally brushed against a plaster moose head, which fell and shattered on the floor.

In Exeter, Reagan was told that a volunteer in the local Bush headquarters wanted one of Reagan's campaign buttons. Reagan walked across the street to the headquarters, a store-front that bore the sign, "Sleeper House of Beauty," and gave her a button, saying that he hoped she would want to vote for him after she had worn it a while.

Earlier, Reagan announced he would meet with six other Republican presidential candidates Feb. 20 in Manchester for a 90-minute public forum sponsored by the League of Women Voters. The format is virtually identical to that of last month's Iowa debate, in which Reagan refused to participate.

Jim Lake, Reagan's press secretary, said negotiations are continuing on a proposed debate with Bush Feb. 23 in Nashua The Reagan campaign is seeking assurances that there would be New Hampshire television coverage of this event.