The American Revolution was already 114 years old when the Daughters of the American Revolution were organized. And since 1890, they have been building a reputation as a group whose eyes are fixed firmly and tenderly on the past.

Midway through its four-day 88th Continental Congress, scheduled to end tonight, the DAR seemed determined to change that image if not much of anything else.

"The one who changed the DAR's image-it would be nice to be remembered for that," mused Mrs. George Upham Baylies, who is completing the second year of her three-year term as president general, although "I don't think it's as bad as some people think it is."

Many of the delegates and pages in Constitution Hall felt the same. "If I could change one thing, I would said Edith Hartley, who started a new chapter last October in Tampa.

Mrs. David Ferrenbach, Missouri state regent, was more emphatic: "I am trying very hard in Missouri to let people know that we are not a bunch of little old ladies in tennis shoes anymore."

With its 3,600 registered delegates ranging in age from 18 to over 100, the Continental Congress generally resembled the national meeting of any volunteer service organization. Beginning with a memorial service on Sunday and ending with a banquet tonight, it included a tour of the White House, reports from all 50 state regents and officers in charge of scholarship programs and other awards, reports on the two schools the organization maintains in Appalachia, and addresses by speakers who ranged from the assistant commandant of the Marine Corps to the publisher of The Washington Post.

The delegates wore ribbons studded with pins and emblems telling the practiced eye of offices they had held, services they had rendered, and how many of their ancestors had been involved in the Revolution.

One member sporting four "ancestor bars " (by no means a record number) was Alice H. Wilson, state regent for the District of Columbia. To become a member, one must prove direct descent from a participant in the Revolution; but for many current members, proof had already been supplied by a mother or grandmother. There is an auxiliary organization, Children of the American Revolution, which one can be enrolled at birth.

"My mother wasn't a member," Wilson said, "but she had cousins who were. They got me interested and I started looking up ancestors.

That's a fascinating subject-I have drawers and drawers of material."

The organization divides its activities into patriotic and educational pursuits.

"I like to do genealogical research," Wilson said, "and I'm lucky living in the District because the DAR has one of the genealogical archives in the right here-we have all the census records through 1900 on microfilm.

"And I enjoy marking graves. We put a bronze marker on the grave of any soldier from the Revolutionary War we can track down. We do a lot of grave-marking if we can find the graves, but there are a lot of ther things you can do if you're interested-school programs, good citizenship awards, planting trees-they have a broad approach; any interest that anyone has besides looking up ancestors."

Membership in the DAR has boomed in recent years. It is now over 208,000 members (up from 189,000 10 years ago), and they support a staff of 143 employes with an annual payroll of about $1.25 million. About onr-third of the new members each year are "junior members" (age 18 to 35).

President Baylies traces the latest surge of interest to the bicentennial celebration and says that "it has kept up since then."

Although she heads probably the most roots-conscious organization in United States, she does not see any connection between the current interest in roots and the growing DAR membership.

"Mr. Haley did a lot of research in our achives," she said, "but 'Roots' hasn't really made any difference in our membership." CAPTION: Picture, Mrs. George Upham Baylies with children in revolutionary dress by Joe Heiberger