The 14-year-old girl in an upstairs classroom at Stuart Junior High School in Northeast said she has changed her mind about school.

"My friends wanted me to hook school with them," the girl explained, and she was easy to persuade because she didn't much like school. "Then I found out I couldn't be nothing in life if I hooked school. I wouldn't be able to get even a cleaning job if I hooked school."

The girl, one of eight students in a support group for truant students yesterday at the District's new Student Attendance Service Center, said the counselors there had talked with her and made a big difference in getting her to stay in school.

She was telling her story to a group of high-ranking visitors, including Mayor Marion Barry, Sen. Arlen Specter (R-Pa.) and Joan Specter, a Philadelphia City Council member and the senator's wife. Accompanied by D.C. School Superintendent Floretta D. McKenzie, they had come to see how well the truancy program had worked since its start in March.

From March 18 to Nov. 1, according to the school system, 484 students were referred to the attendance center, mostly by police who find truant juveniles in the community during school hours but some by the schools and a few voluntary self-referrals by students. About 70 percent were junior high school students.

Specter, chairman of the Senate Appropriations subcommittee on the District, had added $1.1 million in federal funding to the District's fiscal 1985 budget for a truancy initiative. He added $500,000 to the fiscal 1986 appropriations bill, which is still to be considered by the full Senate. School officials said they would use these funds to open two more attendance centers, one across the Anacostia River and one in Northwest.

The initial funding was used largely to buy 78 automatic dialing machines that daily call parents of students who fail to show up for school or who are late. The parents hear a recorded message telling them to call the school to discuss the situation with a counselor. The school system also hired 19 attendance counselors and other personnel.

Chronic truants are referred to the attendance center in Stuart Junior High School at Fourth and E Streets NE for counseling on a short-term or an extended basis.

Attendance citywide has risen from 88.5 percent to 90 percent since the attendance initiative started, officials said.

But at certain schools, the improvement is more dramatic, they said. The attendance rate at Hart Junior High School in Southeast, for example, rose from 82.5 percent in the 1983-84 school year to 91 percent the next year. At Wilson High School attendance rose from 79 percent to 87 percent in the same period, school records show.

Specter called the initiative a "frontal attack" on the city's truancy problem and said Congress will watch how the District's program is working when considering national approaches to the issue.

On the first floor of Stuart yesterday, a counselor was talking with one 17-year-old dropout and his mother. The dropout decided to return to school after his younger brother and sister had gotten counseling at the center, the counselor said.