Five years ago, Demetria Washington and 29 other seventh-graders were promised a dream.

The rules were simple: Stay in school. Take college preparatory classes. Maintain a 2.5 grade-point average on a 4.0 scale. And score 800 or better on the 1,600-point Scholastic Aptitude Test.

The reward was equally simple, if previously unattainable: guaranteed admission into Virginia Tech with nearly all costs paid.

With constant prodding and a lot of help, about two-thirds of that original group of 30 black students from southeastern Fairfax County have lived up to the expectations and are ready to collect.

Now seniors at Hayfield, Mount Vernon and West Potomac high schools, these participants in the Alliance for Increasing Minority Success, or AIMS as it is commonly known, were saluted at a luncheon yesterday as role models by local and state leaders, including Gov. L. Douglas Wilder.

"If kids are encouraged and they're given high expectations, they'll rise to them," Mount Vernon High School guidance director Virginia Williams said in an interview. "These kids were told, 'Look, you can do it,' and they believed that."

The distinctive program, similar to widely publicized offers by millionaires to inner-city youngsters in New York and Washington, selected 12-year-old black youngsters thought to have college potential but who were at risk of ending their education after high school.

For five years, their teachers, parents, counselors, tutors and mentors from county businesses constantly encouraged them and provided a little shove when necessary.

There were weekly meetings with counselors. Teachers volunteered their afternoons to tutor in tough subjects. Businesses such as Chesapeake & Potomac Telephone Co. and TRW Systems provided summer jobs. Counselors stopped students in the halls to make sure they turned in that day's homework. Report cards were scrutinized.

"We started off being spoonfed," said Washington, a 17-year-old senior at Hayfield who plans to be a lawyer. "And now we're feeding ourselves."

"Hey, this is our future that's at stake," said Sermaine Craig, 17, a fellow Hayfield senior who plans to be an accountant and will be the first in her family to attend college. "Now we understand how important it is to us."

If there was a credo for the teenagers, it developed during a two-week stay on the Blacksburg campus of Virginia Tech in the summer of 1989. Their host instilled in them an intolerance of excuses. Whenever someone arrived late or failed to turn in an assignment, the rest of the group recited a saying: "Excuses are the tools of incompetence. Those who use them build bridges to nothingness."

Of the original 30 students, 25 remain in the program, with the rest having moved from the area. Of those, 19 now have the necessary grade-point average to qualify for the reward, according to Leroy Miles, an assistant admissions director at Tech who helped start the program.

For those who qualify by graduation, Tech will pick up 40 percent of the school's $5,743-a-year costs for tuition, room and board. The Fairfax County Public Schools Education Foundation, made up of county businesses that raise money for school projects, will pay 40 percent. The student's family will be responsible for the remaining 20 percent.

For those who qualify but choose to go to other four-year colleges, the foundation will contribute the equivalent of 40 percent of Tech's costs.

Plans to continue the expensive AIMS program never materialized. Instead, the foundation and the school system sponsor a program to link 500 minority students across the county with companies and 19 universities for tutoring and mentoring. Some will receive full scholarships.

While the success stories have been heartening, one teacher who worked with several participants said the program was a mixed bag, with some students profiting from the experience and others in over their heads. "There was just night-and-day difference between some of them and I just never could figure out how {school officials} never looked that far into their academic potential," said the teacher, who did not want to be identified.

Craig recalled being pressured to take English classes for gifted students for three years and constantly getting C's before she decided to go back to regular English, where she got B's.

Rami Evans, a Hayfield senior who turned 18 yesterday, had a particularly rocky freshman year in which he failed algebra and did poorly in his other classes. After taking algebra again during summer school, he said he realized how important the AIMS program would be for him. He raised his average to 2.8.

"I think of it like evolution," he said. "I started off on the bottom and I'm just working my way up."