"I've been around," she said in her living room on Saturday. "Done most everything."

She does not get out of her house on Canary Lane much these days. But tomorrow morning, Mary Chambers will walk slowly on her frail legs into Rancocas Valley Regional High School to do something she has never done in her 90 years.

She is going to vote.

Voting was never something that concerned Chambers. She grew up on Cy Galloway's plantation, where she helped her grandparents and then her parents. "I had to go to work to keep my mother going," she said. "It looked like I was born to wait on old folk." She was also occupied with raising 11 children. "I think I did my part, yes sir."

And, truth be told, voting in tomorrow's New Jersey primary does not especially concern her. Actually, she said she was not certain for whom she would vote. Sometimes these days, she explained, she has a bit of a problem with her memory and hearing.

"Who you going to vote for, Mom?" asked Lucille Hoskins, 66, who lives with Chambers.

"Who?" her mother responded.

"Who was that man that came by asked you to vote for - the Rev. Jesse Jackson?" Hoskins asked.

"That who you voting for?" Chambers said.

Hoskins is voting for Jackson. And the people who operate Jackson's campaign in Burlington County will try to make certain that Chambers, too, will cast the first ballot of her life for their candidate. After all, they were responsible for registering her to vote.

In the words of Jackson, Chambers is a rock, a symbolic rock.

*

Occasionally on the campaign trail, Jackson delivers his "David and Goliath" speech to illustrate how blacks can defeat President Reagan in November, likening the task to the biblical confrontation between David and the giant.

"Well, Reagan is the giant of our day," Jackson says. "But don't let him scare you. He can't ride on the horse all the time. He's got to get down and walk sometimes. . . .

"Little David, pick up your slingshot, pick up your rocks, say 'Your time has come.' In 1980, Reagan won, not because he was such a giant, but because little David didn't pick up his rocks.

"He won Illinois by 300,000 votes. There were 500,000 unregistered blacks, about 300,000 unregistered Hispanics. Rocks - unregistered voters - just laying around.

"He won Alabama by 17,000 votes; 260,000 blacks unregistered. Rocks just laying around.

"He won Mississippi by 11,000 votes; 170,000 blacks unregistered. Rocks just laying around.

"He won Tennessee by 4,000 votes; 180,000 blacks unregistered. Rocks just laying around.

"He won North Carolina by 39,000 votes; 505,000 blacks unregistered. Rocks just laying around.

"He won eight Southern states by 180,000 votes; 3 million blacks unregistered. Rocks just laying around.

"That was 1980. We've changed our mind. Little David, pick up your rock and your slingshot. Our time has come."

*

Clarence Coggins, New Jersey state coordinator of the Jackson campaign, said his organization did not emphasize voter registration. "That wasn't the focus," he said. "The focus was to win with what you had."

Perhaps Coggins was understating the voter-registration effort. Many of his county coordinators reported large numbers of new registrants, an indication, they said, of newly born political awareness among minority voters.

Across New Jersey, according to the secretary of state's office, about 3.7 million residents will be eligible to vote tomorrow - up about 150,000, or 4 percent, from the 3,550,000 registered before the last presidential primary in 1980.

Washington Georgia, Jackson's Burlington County campaign coordinator, said his group registered at least 1,000 voters, including Chambers and a 91-year old woman who also has never voted.

The Jackson campaign will contact the new voters before tomorrow to make certain that they understand how to vote and that they have transportation to the polls.

Chambers, like her daughter, said she felt proud that a black man was running for president. "It be a good thing," Chambers said, although she said she knew little about Jackson or politics. "To tell the truth, I didn't pay it no mind."

The mother and daughter were raised when bigotry was more pronounced, when "equal rights" was only a feeble clause in the Constitution. Chambers worked the fields, minded her business. Voting was something other people did.

Of course, she said, times have changed. "I figure like this: God made one like the other, the white man like the black man."