“I’d rather focus on getting fit than getting plastic surgery.” -Barbara Shimaski, 49, Manhattan

YOU’VE come a long way, baby – and you can run even farther.

That’s the thinking behind the More Marathon in Central Park on Sunday, the first 26.2-mile race exclusively for women 40 and older.

“I actually feel stronger than I did five years ago,” says 42-year-old Jill Van Note, who juggles her training for marathons – this is her third – between acting and day jobs.

“You do have to be selfish with your time, especially when you run anywhere from 12 to 20 miles at a time.”

So far, 2,380 women from around the country, Canada and the Bahamas have signed up to go the distance – or, at least, half of it with a female friend age 11 or older.

Not that the over-40-and-female set has been left in the dust.

According to Susan Crandell, editor-in-chief of More magazine, the race’s sponsor, 40 percent of the women who finished the 2003 Ironman Triathalon in Hawaii were 40 or older, as were 35 percent of the women who finished the last New York Marathon.

“One woman is running her 22nd marathon, another is running her first after a liver transplant,” says Crandell, 52, who last year climbed Mount Kilimanjaro.

“Our readers have been breaking rules all their lives and we’ve found they’re eager to show the world how fit they are.”

The oldest runner signed so far is 81-year-old Helen Klein, a multiple-marathoner and ultra-distance runner from Sacramento, Calif. She finished the Napa Valley marathon course last year in just under 4 hours and 41 minutes.

Other women have signed up to shed post-pregnancy pounds or set new goals.

“I’d rather spend hours training than at the shrink, and I’d rather focus on getting fit than getting plastic surgery,” says Barbara Shimaski, who turns 50 in May.

Shimaski, who owns a graphic design firm, is a racewalker – she stopped running because of injuries – and did her first New York marathon this year.

“Racewalking is odd-looking, but it’s much easier on the body,” she says. She steals time from work and “disappears” every Saturday morning to run in Central Park.

“Lo and behold, the stress washes away,” she says. “I can worry about aches and pains instead of other issues.”

For Bari Chase, a 50-year-old lawyer, mother and real-estate agent in Manhattan, running has been downright remedial.

She has a chronic blood disorder that leaves most people weak and tired, but it hasn’t stopped her from running 21 marathons. On Sunday, she’ll make it 22.

“I’m not on medication, I have a 12-year-old daughter, and I’m running marathons,” she tells The Post proudly. “The hematologist says, ‘Whatever you’re doing, keep doing it.’ ”

Still other women run marathons just for the sense of accomplishment.

“As an actor in New York, you can be talented and train and still never get to do the thing you’ve trained for,” says Van Note.

“With running, you go out, put in your time, prepare – do all the things you do when you act, only here you actually get to do it!”

Like many marathons, this one benefits a cause: A portion of fees will benefit Step-Up Women’s Network, which helps women and girls with various services.

Online, phone and fax registration ends at 5 tonight at http://www.nyrrc.org or at http://www.moremarathon.com. Latecomers can register in person until Saturday at New York Road Runner headquarters at 9 E. 89th St., between Fifth and Madison avenues.