Mary Cotter has been a high school swimming champion, a swimming instructor and a conservationist. And for her 103rd birthday, she was Wonder Woman.

Dressed in a costume given to her by friends (complete with tiara and bracelets), Mary celebrated Monday at the Montclair Senior Center in Montclair, California, where's she's volunteered for 25 years. However, this superhero didn't just sit down and soak in the attention; she served drinks as she does five days a week.

"They call me the barmaid because I'm serving drinks," she told KABC-TV.

Despite her age, Mary lives alone, and drives herself to and from the senior center. Her secret? "Just keep busy I guess."