Only about one-fifth of the students who will comprise the Class of '63 in the "Sister Seven" women's colleges were accepted under the new early application program, it was announced this week. Accordingly, Radcliffe doesn't anticipate any over-acceptance of students, said Miss Constance E. Ballou, director of Admissions.

The early application program, inaugurated this year, allows girls to find out whether they have been accepted by the college of their choice in mid-December, rather than some time in the spring.

To be eligible, they must be recommended by their high school principal, cannot apply for more than one institution, and must have taken both their S.A.T.'s and College Board achievement tests in their junior year.

Miss Ballou termed the program successful, although she said that over-application might become a problem when the new policy becomes more widely known.

There had been some feeling that girls, well qualified for acceptance, would have to be refused because only a fraction of the full class could be let in in December. Miss Ballou pointed out, however, that students who were close to being accepted would receive letters encouraging them to re-apply. A second application will mean that they take College Board tests this year, she said.

Every school participating in the agreement except Radcliffe sent out letters of admissions yesterday. Radcliffe is scheduled to mail their notices by Dec. 15.

The "Sister Seven" colleges are: Vassar, Smith, Wellesley, Mt. Holyoke, Radcliffe, Bryn Mawr, and Barnard.