New Jersey woman celebrating 100 years on her 25th birthday

ATCO, N.J. (WPVI) -- Kathryn Marshall was born on February 29, 1916.

That was leap day 100 years ago.

Some might argue since the day comes just once every four years, Kathryn is really only 25. But she doesn't care about the leap year math, she's just happy to be here.

"Oh yes, better than the alternative. That's what I think," Kathryn says with a laugh.

Less than 1% of the world's population was born on leap day, making them rare birds to start with, but then how many of them make it to 100?

"Sometimes I feel like 100, and then sometimes I feel about 60," Kathryn said.

Kathryn is a resident at the Fountains in Atco, New Jersey where she still lives in her own apartment and is seen regularly tearing through the halls with her walker.

"She walks faster than anybody in here and she's 100 today; she amazes me. She's as sharp as a tack," resident Joan DiFlorio said.

Kathryn goes to exercise class three days a week and the teacher says she's an inspiration to everyone.

"The younger residents, during the exercise class, always point to her and say if she can do it, I can," activities director Susan Mantz said.

Kathryn has outlived two husbands and her son and daughter.

One of her great-grandchildren sent a giant birthday card from his third grade class and her apartment now looks like a flower store.

"I got a pile of flowers and I got a pile of candy and a lot of money, which is good," Kathryn said.

Instead of throwing a party, Kathryn donated $100 to the Atco food bank.

Friends and staff at the Fountains kicked in over $300 more in honor of this leap year centenarian.

She says, "Nobody gets away free. Everybody has sadness and they have happiness."

And what is Kathryn now?

"Happy."