Mary Cotter is a real-life Wonder Woman. The 103-year-old recently celebrated her birthday at the Montclair Senior Center, California, where she’s been volunteering for the last 25 years. Cotter’s friends bought her the costume, and the residents affectionately call her their “barmaid” because she serves them tea, coffee, and water.

What’s the secret to living a long life, according to Cotter? “Just keep busy, I guess” she told ABC news. In 1930 Cotter helped her high-school win the state swim championship, she was a children’s swim instructor into her 60s, and was still helping rescue see turtles in her 90s.

(h/t: abc7)

Ms. Cotter is a real Wonder Woman but not just because of her costume

She’s been coming to volunteer at this senior center for the past 25 years

The secret to her long life? “Just keep busy, I guess”

Watch a news report about Mary Cotter below: