FORT JACKSON, S.C. — The Army is beginning basic training for the oldest recruits in its history, the result of its concerted effort to fill its depleted ranks during the Iraq war.

In June, the Army raised its enlistment age limit to just under 42, the second time it has raised the eligibility age this year. In January, it raised the limit from 35 to just shy of 40.

Now, the first group of older recruits is going through training here. So far, only five people 40 and older — and 324 age 35 and older — have enlisted, Army records show.

Army Pvt. Margie Black — a 41-year-old grandmother and former prison guard from West Columbia, Texas — is one of them.

She's more than twice the age of the never-been-away-from-home teenagers who fidget and fret at the L. Mendel Rivers complex, the Army's front door to the newly enlisted. She has been here less than a week, and her calm demeanor has earned her a nickname.

"They call me Mom. They do it in a respectful way," she says. "I respect them, too."

When Black was 19, she wanted to join the Army. Pregnancy with her daughter, Ashley, prevented that. A year later, Nathalie came along, followed a year after that by daughter De'Na.

Black got a job as a prison guard, raised her family and pretty much forgot about being a soldier.

When Ashley, now 21, got serious about enlisting, the notion of Black joining her daughter seemed impossible. Her recruiter, Staff Sgt. James Alston, dropped Ashley off at home and joked with Black about signing her up.

A few days later, Alston called Black to tell her the Army had raised its eligibility limit to a day short of 42.

"She said, 'Stop messing around with me,' " says Alston, who convinced her he was serious.

"She said it's an act of God that she's going to be able to join," Alston says. "Her daughter joined on Monday; she joined on Friday."

To accommodate the older soldiers, the Army has lowered the minimum physical requirements needed to pass basic training.

David Chu, undersecretary of defense for personnel and readiness, says the improved health and fitness of middle-aged Americans makes it possible for them to enlist.

"People are living longer and are much healthier and physically fit into older ages than was true in earlier generations," Chu said.

The Army has the military's highest age limit. The Air Force and Marines' limits are 27, while the Navy's is 35.

Allowing older soldiers makes sense if done properly, says Loren Thompson, a military analyst at the Lexington Institute, a nonpartisan think tank in Arlington, Va.

"For front-line combat troops, it's a bad idea," Thompson says. "But nobody is proposing putting 42-year-olds next to 18-year-olds on combat patrols. If it is correctly run, it could be a real boon. You don't chase away people ... just because they've reached some arbitrary age."

So far, the Army, which supplies most of the troops for the wars in Iraq and Afghanistan, is on track to meet its recruiting goal of 80,000 new soldiers this year. In 2005, the Army missed its 80,000 goal by 8 percent when it recruited 73,373 new soldiers.