A few weeks later school advocates took over a hearing on county construction projects. Of the 45 people signed up for comment, more than 40 spoke about schools.

‘‘One person spoke about libraries, but ... kind of got drowned out,” said Commissioner Jan H. Gardner (D).

As Frederick County Public Schools gained more students in the last couple of decades, their needs have become a driving force in the way the county budgets, spends or saves money, how it prioritizes projects and how it plans for the future.

That could change. In the next two decades, another group is likely to dispute schools’ reign over county funding and attention — the Baby Boomers.

A study from the Frederick County Department of Planning projects that between 2010 and 2015, residents 55 and older will, for the first time ever, outnumber schoolchildren.

‘‘Never before has Frederick County experienced this type of age shift in the population,” the study states.

The aging Baby Boomers could place different demands on Frederick County.

‘‘Whenever there is a shift in the composition of the county’s population, it is reasonable to expect a shift in the demand for services,” said Hal Keller, the school system’s director for fiscal services. ‘‘Increasing pressure on county government to fund non-education services will definitely complicate the ability of [the school system] to fund future service increases.”

The need for space

With or without the growth of the Frederick County elderly population, the school system will still need an aggressive program of school construction to accommodate all incoming students, according to Ray Barnes, director of facilities for county schools.

‘‘There will be more elderly people,” he said. ‘‘That doesn’t mean that other age groups aren’t growing as well. The number of students is going to continue to increase because the total number of births is going up.”

Frederick County’s school enrollments won’t explode as they did in the 1990s, but they will still climb. By 2015, equated enrollment (which counts each pre-school student as half a student) is expected to jump to 43,646.

That means more pressure for the already overloaded school system, which even now struggles to accommodate 40,315 students inside 63 schools. With 20 schools operating over capacity, the system relies on 151 portable classrooms to provide enough space for students.

‘‘My challenge is to convince people that the school system is going to continue to grow,” Barnes said. ‘‘This issue of school overcrowding is not going to go away as long as Frederick County is on the outside of the capital of the United States.”

As Baby Boomers retire, investing in education will become even more important, said Jan H. Gardner (D), president of the Frederick Board of County Commissioners. ‘‘As the Baby Boomers retire ... there is going to be a real need to have a very educated and highly effective workforce,” she said.

While Baby Boomers will affect the school system, officials agree it is impossible to predict the full impact. Outspoken Baby Boomers may try to cut in front of schools in the county’s line for funding. The school system then may need to explore other avenues to secure money for its growing population.

School board members agree they have options — from developer-funded school construction to making the school system’s budget a fixed percentage of the county’s. Some say the effect on the school system may be minimal. Baby Boomers who retire in good health, with savings and insurance, are not likely to be a burden for government, said Katie Groth, school board president.

‘‘We always have to be prepared for demographic shifts, just as we always should be prepared for shifts in the funding available for school operations and construction,” Groth said. ‘‘But we are not in the business of doom and gloom and hand-wringing about dire possibilities. We cannot control the future, we cannot predict the future, and so we just keep doing the best we can ...”