Antoinette Cataldi Sessa decided her career as a D.C. school guidance counselor had ended too soon when she was forced to retire this year at age 70 under the city's mandatory statutes governing school employes.

She asked the Board of Education to eliminate mandatory retirement, and when the board declined she set up a one-woman picket line in front of school system headquarters. Then she asked the board to waive the rule for her, and again the board ruled that she had to leave her job at Jefferson Junior High School.

Now, after meeting with Sessa, City Council Chairman David A. Clarke has introduced a bill that could make it easier for Sessa and other school employes to work past age 70.

School Board President R. David Hall has sharply protested Clarke's bill, calling it an "unwelcome intrusion" on the board's powers. But Clarke, who said he did not introduce the measure specifically on Sessa's behalf, contends that the school system's mandatory retirement rules are deficient because they do not allow discretion on the part of officials. He said that only the City Council can correct the problem.

As for Sessa, she saw Clarke's measure as "crumbs," but better than nothing.

"I've only worked for 22 years. I got my college degree at age 45, after raising six children," said Sessa, a grandmother 13 times over. "This 'mandatory retirement' is a vulgar word.

"It's age discrimination, that's what it is," she said. "It's archaic. It's abusive toward the elderly. It's demoralizing. It leaves you feeling like you've been thrown out with the trash."

Sessa said she is pleased that Clarke drafted the bill, which has been referred to the council Committee on Education, chaired by council member Hilda H.M. Mason (Statehood-At Large). But, she said, the bill "only scratches the surface of the problem."

"Being that I came through the Depression and came up the hard way, I'll accept crumbs, if the crumbs are leading in the right direction. The bill is going in the right direction, but it's not going far enough. I'm going to fight and fight until this city knocks out mandatory retirement completely."

Under the current law, a two-thirds majority vote by the school board is required to retain a teacher or counselor who has reached age 70. Clarke's bill would allow a simple majority to waive retirement but would set criteria for the board to consider, including length of service and performance evaluations.

Clarke, who favors mandatory retirement at age 70, said, "I believe that any law that requires a judgment ought to have some criteria for the exercise of that judgment."

Clarke maintains that school system retirement rules, as part of the D.C. code, "can only be changed by the City Council or by Congress."

Among the District's civil service employes, only law enforcement officers are covered by mandatory retirement rules.

Sessa, whose retirement pay is a third of her former $35,000 salary, said she believed that she was providing a good role model for students. "I was telling the children, 'You've got to fight for what you believe in . . . . ' I can't have people step on me just because it's the law.

"Segregation was law once, too. It was a dumb law . . . and it was changed . . . . Racial discrimination, age discrimination, it's all the same."