— -- Mary Margaret Sims turns 90 years old this Easter weekend, but if you see her in motion, you just might not believe it.
She is a familiar face in Fremont, California, an hour south of San Francisco, where she is a faithful Meals on Wheels volunteer. Her 90th birthday is on Saturday.
With the strength and vigor of someone much younger, and a heart of gold, Sims jumps into her car every Wednesday and drives door to door to deliver meals to people who rely on her because they are sometimes too sick or frail to leave their homes.
Sims reaches about 23 households on those days, and usually doesn't miss a beat, according to Patricia Osage, executive director of LIFE ElderCare, the organization that runs the Meals on Wheels program in Fremont.
"She has been volunteering for 31 years and we've only been delivering meals for 41 years," Osage said with a laugh. "But she'll say, 'Oh no, it wasn't 31 years because I took a few months off in 2007 when my husband passed away.'"
Sims couldn't be reached for comment by ABC News.
"She tells us she got back out of bed because Meals on Wheels needed her," Osage said. "And we did."
"Serving others gives us self-satisfaction," Sims told local news station Fox 13. "So that's how come I am still driving around delivering meals."
Meals on Wheels America Communications Vice President Jenny Bertolette told ABC News that Meals on Wheels "delivers nearly one million meals a day to isolated, home-bound older adults," across the country. The program serves 2.4 million seniors each year, relying on almost 2 million volunteers, added.
The irony is not lost on Osage that Sims is much older than many of the seniors she serves.
"She is an inspiration because she's incredibly kind," Osage said. "She has an enormous heart. ... She goes above and beyond."