Five months ago, on April 8, Judith Weisman signed a sworn affidavit that she would not send her daughter, Beth, to kindergarten at Rosemary Hills Elementary School in Silver Spring, a cornerstone in Montgomery County's school integration plan.

Weisman's affidavit said she would enroll her daughter in the private Jewish Day School. Thirty other parents from Chevy Chase signed affidavits citing similar intentions of enrolling their children in private schools.

A month ago, Weisman, after much introspection, changed her mind. Now, Beth, along with about 14 other kindergarten-aged Chevy Chase children, boards the school bus every morning in her predominantly white neighborhood for the four-mile ride to Rosemary Hills, a school where the student body would be more than 90 percent minority without a busing plan.

"I'm still very cautious. But I decided to give it a shot," Weisman said yesterday. "It seems to me that the school board has made a solid commitment to providing resources for the school and Beth has an excellent teacher." The teacher, Weisman said, is the same one who taught her son at Chevy Chase Elementary.

Beth Weisman is an example of some of the unexpected students school officials referred to at Monday night's board meeting when they announced that the overall kindergarten enrollment at Rosemary Hills had exceeded their expectations by nearly 50 percent.

One-hundred and forty children had been assigned to kindergarten at Rosemary Hills this year. But school officials, anticipating a snowball effect, expected enrollment might drop as low as 70 after 31 of 42 parents of Chevy Chase kindergarteners submitted their sworn statements in April to the State Board of Education.

School officials said Monday night that 104 students have enrolled in kindergarten-the only class participating this year in the busing plan-and that the enrollment was split evenly between minority and white students. Rosemary Hills principal Ruth Spearman said yesterday that at least 15 of those students are from Chevy Chase.

Under the busing plan approved by the board in March, kindergartners are bused from the predominantly white Chevy Chase and North Chevy Chase Elementary School areas to Rosemary Hill. (Eventually, first and second graders from these areas will also attend Rosemary Hills.) Children from Rosemary Hills are bused to Chevy Chase or North Chevy Chase for grades three through six.

Rosemary Hills had been paired with Chevy Chase for six years and was the symbol of the county's voluntary integration efforts when the school board voted in 1981 to undo the plan. That decision was reversed last March by a newly elected school board, but not without considerable opposition from some Chevy Chase parents who complained that wide economic differences between children from the two areas would interfere with their children's education.

"When I was asked to take on this job last year I was told we might get only four students from Chevy Chase and I was quite concerned," said Spearman in her office, pointing to the map dotted with pins representing students. Spearman met with groups of parents 13 times before the beginning of school in an attempt to persuade them to give Rosemary Hills a chance. "While we don't have all the students we would like, I am very excited about what has happened," she said.