Like many youngsters, Gina Gordon attended Sunday school, but her mother was increasingly concerned because Gina was "just getting older and older and being put with children younger and younger, so by the time she was 12 years old, she was with children 6 and 7 years old."

"That wasn't so good socially or for her self-esteem," said Dollace Gordon, so she began looking for an alternative for Gina, who has Down's syndrome. What she found was a Sunday school where Gina, now 20, and other adults with some form of mental handicap have developed fast friendships and positive views of themselves and their abilities.

The interdenominational school is the creation of Catherine (Bobbie) Meyer, whose techniques have been refined by more than a quarter of a century of practice. Housed in a building owned by First Trinity Lutheran Church at Fourth and E streets NW, the school has adopted a rare approach for this area, according to spokesmen for the District of Columbia Association for Retarded Citizens (DCARC). Other programs for the mentally handicapped generally involve younger students or trying to "mainstream" them in regular classes.

Meyer's 25 students of several faiths range in age from 16 to 40 and in educable level from 4 to 8 years. Most are moderately retarded, but a few are mildly or severely so, and some have accompanying psychological or emotional problems or neurological disorders such as cerebral palsy.

Along one wall in the narrow classroom is a shelf of trophies, most from the Special Olympics. Each student has received an honor of some sort. Next to the gleaming badges and crisp certificates is a sign with an inscription from I John 3:18 that sums up Meyer's goals and efforts: "My children! Our love should not be just words and talk; it must be true love, which shows itself in action."

"I want them to grow in their faith and I only have one time a week to do this," said Meyer, who also is interested in development of the "whole person"--improved physical dexterity, memory skills, and interpersonal relations.

Usually at least 15 show up at 9:30 a.m. Sundays for 1 1/2 hours of action-oriented lessons that require 20 to 30 hours of teacher preparation each week.

"Some people think you can just get up here and read the Bible to them," but visual aids get the message across, said Meyer, who often acts as one herself if a slide, picture or flannel cutout isn't there at the precise moment needed. At the mention of a camel during a recent class, Meyer instantly became one, hunching her small agile frame and lumbering down the aisle.

The key to Meyer's success, parents say, is student participation. "She involves the kids thoroughly in the lesson," said Gordon. "It's not one of those things where she just stands up and talks to the kids. They're always part of it."

In general, the scene resembles any early-age classroom. Typical lessons involve pictorial displays of Bible stories, with the students taking turns adding cutout figures to a backdrop propped on a large easel or setting up statues in a sandbox. Other activities involve filling in the blanks, taping on the appropriate word to complete simple sentences handwritten in large block letters.

Reward for correct answers is immediate and enthusiastic, with vigorous applause often led by the students themselves.

Student Ricky Lee has cerebral palsy. He sat at a recent class with friends Gregory Lampkin and Mario Magette. When it became his turn to go to the front of the room and fill in the blank for a story, Gregory and Mario whooped with delight, slapping him on the back and shouting, "Go, Ricky, go!" He answered correctly, received his applause and returned carefully to his seat, where Gregory shook his hand and said proudly, "My boy, my boy."

Meyer acknowledges that teaching methods have changed since the early, more experimental days at Bethlehem Lutheran Church in Anacostia, where she and her husband Leroy started their first school on Saturdays in 1954. Then, classes were "too verbal" and less structured, she said.

The lack of suitable instruction materials is one reason why so much preparation time goes into each class. Meyer, in fact, has developed a confirmation manual soon to be published by Bethesda Lutheran Home in Wisconsin, where her mentally handicapped son Steven, 32, lives.

Steven's disability sparked his parents' interest in religious education for retarded children. He was part of the first class and his sister Nancy, 26, also mentally handicapped, attends now.

Four current students started with the original group, when the Meyers first contacted DCARC, then known as Help for Retarded Children Inc., to get a mailing list of families with mentally handicapped youngsters. Nineteen were enrolled in the first group, and throughout the years classes have remained, on the average, about the same size.

Programs like this one are unusual locally and nationally, said Carleston Robinette, head of DCARC's Religious Services Committee, partly because of clergy uninterest: "I had one clergyman tell me, 'Well, they're God's chosen people, they don't need any help' " in religious instruction.

The committee is prepared to help other churches in developing similar programs and can be reached at 529-5020.

According to Meyer, the Rev. David Preisinger, pastor of First Trinity, and his 200-member congregation have been most supportive. Preisinger, who sometimes plays his guitar for the class, attributes Meyer's success in part to the "extreme personal interest" that she takes in each member. That interest stays with the students when they leave, to move with their families or to an institution. Meyer keeps in touch with a dozen such former students by mail and phone.

Meyer finds her work satisfying, with the only frustrations "in myself when I have tried so hard and haven't gotten across to the young people," she said. "But then I go home. . . change my approach and try again the next week."

Sometimes, says assistant Elizabeth Powell, "you have to be able to say things in more than one way." Other times, one way is enough, as when Gregory Lampkin took his turn selecting a song. When he chose "I Belong to Jesus," Powell prompted, "And he belongs to . . . ?"

"Me!" Gregory shouted. "How do you know?" she pursued.

Gregory pointed to his forehead: "My brain right here."