The old are not as old as they used to be.

People over 65 are the fastest-growing population group in America today, and many of them, being active and curious, are flocking back to college. They are "graying the campus," as a recent report by Ruth Weinstock for Educational Facilities Laboratories puts it.

Yet despite this visible graying, the ed biz is still woefully unprepared to accomodate the elderly. The rule, according to the EFL report, is that older adults are admitted only on a space-available basis, mostly to adult courses.

There are two things wrong with that: (1) the space-available restriction implies second-class citizenship, and (2) the prevailing style of college classrooms and teaching methods is inappropriate for people who have not been inside a school for 40 years.

EFL is a nonprofit organization established 20 years ago by the Ford Foundation to encourae and guide constructive changes in school buildings.

College and university administrators, says EFL's Weinstock, should welcome the fact that 1.7 million Americans over 55 years of age are already enrolled in formal education of one kind or another. We are running out of kids to teach. The young college population (18 to 24 years old) will drop by 4 million -- from the present 29 million to around 25 million -- by 1990.

What the parents and grandparents who are taking their place are still up against on campus and elsewhere is what gerontologist Alex Comfort calls 'ageism' -- prejudice against the old -- which, like racism, is based on fear, hangups and folklore.

The dominant culture is still the youth culture. The noisy majority, encouraged by television, newspaper feature sections and slick magazines, still finds it necessary to dress, groom talk and behave below its age.

But the aged, if not yet honored, are at last being recognized. The trend to raise the compulsory retirement age from 65 to 70 is a welcome one.

If demographers are right, one in every six Americans will be over 65 by the year 2030. And a rapidly growing number of the roughly 42 million Americans over 55 years of age are enrolling in institutions of higher education. The buzz word is "intergenerational learning." The EFL sees it as part of a broader tend:

"All Americans today feel a need to recapture the sense of self that the mass society has snatched from us. To some extent all of us feel that we have lost control over our lives. The older people feel this more deeply than other adults because the loss of control -- physical, economic and familial -- is more dramatic and more severe than that of younger people.... Because education is important to the restoration of such control, the need of older people for education is as great as and perhaps more acute than that of people who are younger...."

Yet the relutance to welcome the old to academe persists. One reason is the conscious or subconscious notion "that to be old is to be defunct: poor, feeble, sick, isolated, intellectually moldy, rigidly opinionated and asexual despite all the jokes about 'dirty old men')," says Weinstock. The selves believe this nonsense -- except perhaps Arthur Rubinstein (90), Buckminster Fuller (81), Linus Pauling (78), Averell Harriman (87) and the countless other old Folks who continue to enrich our lives.

It is also nonsense that older people have a monoploy on poor health, insufficient income, adjustment problems, loneliness, denial of their sexual needs and capacities, or poor transportation. It seems teen-agers are far more affilicted by these problems than most older people.

Weinstock's report states flatly that, contrary to popular opinion, learning capacities and intellectual abilities among healthy people grow with the years, rather than diminish. The hang-ups are with the younger teachers, not the older students. Even physical fitness programs, including belly dancing to exercise stomach and hip muscles, yoga and basketball have been as popular and successful as any "mush courses" -- special classes condescendingly tailored for old people.

"Stay away from 'golden age garbage,'" say experienced educational psychologists. They advocate honest, challenging courses in literature, history, philsophy, sociology and anthropology to older persons who have not had previous exposure to these topics.

Mixing old and young on campus is not always easy. At Case Western Reserve, it was recently reported, the first old people were greeted by their younger fellow students with shouts: "Go home and die!" In time, however, it was recognized, says Weinstock, that "the old can serve as positive models of aging."

EFL expects that in the years to come millions more aging people, encouraged by the "Mondale Bill of Lifelong Learning" of 1976 and "The Age Discrimination Act of 1975," will enroll for all kinds of academic activities. Universities and colleges had better get ready for them. The physical adjustments needed are no different than those legally required to help the physically handicapped to get around.

In the end it is not only the old who benefit.

At Fairhaven College in Bellingham Wash., a part of Western Washington State University, old-timers -- so-called "Bridgers" -- have learned and lived together for several years now. The young students have learned to like this as much as the old ones. They told an evaluator, according to Weinstock, that it's mainly the "Bridgers" who keep them at Fairhaven.

"It's a normal community situation, rather than a university ghetto," said one youngster.

"This is real," said another, "not just out of books."