Many of the 300 guests at Friday night's $50-a-plate testimonial honoring Marion Hazel Elliott Jackson for her 43 years of community service were shocked to learn that she will be 81 years old May 30.

A trim, energetic woman wearing horn-rimmed glasses and sensible shoes, with just a tad of makeup adorning her light complexioned face, Jackson has the bearing of a woman half her age.

"I never hide my age; I just never think about it," Jackson said. "No one ever questions it. I do everything everyone else does."

She has dined with every president since Franklin D. Roosevelt, once had a private audience with the late Pope John VI and worked with the late black educator Mary McLeod Bethune.

She has run her own real estate firm for 19 years, presided over a dozen influential civic organizations and volunteered uncounted hours to community service.

"Marion H. Jackson Day," Friday, was arranged by a few of her friends and was officially proclaimed by Mayor Marion Barry.

Jackson was chauffered in a white Rolls Royce for the day. At the dinner she received a full-length black mink coat and other gifts.

During the dinner, attended by City Council members, city business, community and religious leaders and Jackson's son, Linwood B. Elliott Jr., at the Washington Hilton, a slide presentation showed Jackson with Bethune, and with former first ladies Rosalynn Carter and Pat Nixon.

News clippings flashed on the screen showed her accepting awards, working with children, standing with mayors and, recently, working in the office of her company, Brookland Realty. When she opened the firm in 1964, she was one of three women brokers in the city, but she had no problems fitting into the mostly male business community.

"I'd go talk to bank presidents and think nothing of it," said Jackson in her modest office at 2636 12th St. NE, where a glass cabinet in the hallway is filled with trophies, plaques and citations marking her civic contributions.

Looking at a photograph on the wall of her and Pat Nixon at the White House, Jackson recalled that the former first lady was whispering in her ear at the time: "Marion, why can't there be more love in this world."

Shrugging at the numerous White House invitations she has received, Jackson, a political independent, said, "You get on a list and your name stays there."

Her confidence springs from her upbringing, she said, on a 72-acre farm near Brimfield, Mass. Hers was the only "colored" family, Jackson said, but white residents there treated her like any other child, so "I always had the freedom to be myself."

Bethune had a profound effect on her life, Jackson said.

"She was a second mother to me. I think what drew me to her was her earthiness and her sense of religion. Everyday, before we worked, we prayed together," said Jackson, a longtime member of St Luke's Episcopal Church.

At the dinner, the ushers were Girl Scouts because Jackson was once president of the District Council of the Girl Scouts. In all, 27 organizations to which she belongs were represented, including 11 in which she holds office.

Jackson is on the board of the D.C. Chamber of Commerce and the Episcopal Church Women, Diocese of Washington; treasurer of the Howard University Women's Club; a life member of the NAACP; and a charter member and parliamentarian for the Washington Urban League Guild.

She has been president of the D.C. Branch of the YWCA and the Washington section of the National Council of Negro Women.

"She is as active now as she was 30 years ago," said Dorothy I. Height, president of the National Council of Negro Women.

"She drives hard, but she does it in a way that makes it look easy," said James (Bud) Ward, a Marriott Corp. executive. "She doesn't like to waste time and she stays away from those who do."

"She is more than a joiner; she's a leader," said Ruth Bates Harris, an Interior Department human relations officer who calls Jackson "my role model."

Harris said Jackson "was on the committee to help integrate the police department. Out of those meetings, the first black police chief was appointed."

Harris also recalled that when she was on the board of directors of the D.C. Chamber of Commerce, Jackson went with her to a board meeting. "Five minutes after she paid her dues, she was appointed to chair a committee. That's indicative of her involvement," Harris said.

"It's hard for me to say no when I know there's a job to be done. I try to do unto others as I would have them do unto me," Jackson said, adding after a pause, "I try to even do a little better."