BRIGHTON -- Everyone asks Sister Rita Welch for the secret to living to 100.

Sister Rita, a Sister of St. Joseph of Boston who celebrated her centennial on Aug. 19, always has the same answer -- there is no secret.

"It is pure gift," she said, though she added that having "a loving family and community" certainly helps.

"Being part of a group of dedicated women whose charism of unifying love and service to God and the dear neighbor without distinction in the Archdiocese of Boston for over 150 years makes me very proud," she added.

Sister Rita has been in religious life for 82 years. After 50 years of serving as a teacher and principal in the Archdiocese of Boston's Catholic schools and administering the Sisters of St. Joseph retirement home in Framingham, she retired from active ministry and moved into the sisters' Brighton motherhouse in 2005. To celebrate her 100th birthday, the Sisters of St. Joseph had a 71-person dinner of spaghetti and meatballs -- her favorite food. To drink, she enjoys ginger ale, lemonade, and the occasional glass of wine.

"She knows how to celebrate and enjoy life," said Sister Maureen Doherty, with whom Sister Rita shares an apartment.

Sister Maureen, 86, has known Sister Rita since 1971.

"It's been a gift," she said. "Rita is an amazing woman, very giving, very warm, very thoughtful, very easy to live with."

Sister Rita helps her roommate with cooking and cleaning when she can, saying Sister Maureen "makes sure I don't overdo it." She still volunteers at the motherhouse and serves as a receptionist once a week.

"Wherever there is a need, and I can help, I try to do it," she said. "I also have more time to spend in prayer, which delights me."

In her spare time, she likes to read, do puzzles, and play Rummikub and Scrabble, which keep her mind sharp. She also dabbles in painting and poetry.

"I feel blessed to be 100 years old," she said. "It is a special grace given to me by a loving God."

Sister Rita grew up in Framingham. Her childhood, though marked by the Great Depression and World War II, was a loving one.

"My parents made sure that we had everything despite the hardships that the war and Depression created," she said. "My parents instilled in us Christian values that remained with me throughout my life."

Her childhood memories include walking to 7 a.m. Mass every morning during Lent, and kneeling in the family parlor to pray the rosary every evening in October.

"We also lived in a neighborhood that looked out and cared for each other," she said. "It was a happy childhood."

Thoughts of entering religious life came as she was working a corporate job after high school.

"I tried to dismiss them, but God kept nudging me," she said.

She entered the Sisters of St. Joseph of Boston's novitiate in Framingham, then attended Regis College and earned a master's degree in reading. She served as principal of St. Bridget and St. Tarcisius Schools, both in her native Framingham.

"The many years that I taught in so many schools in the archdiocese created memories and friendships that I will never forget," she said. "I also think about the many beautiful women that I lived and worked with over the years and how they helped me and shaped me to be not only a good person but also to be a faithful and dedicated woman of God and the Church."