A small, intense figure in the second violin section, Caroline Libby is there at every rehearsal. She skipped a few when she had breast cancer in the early 1990s, but she came back with a hunger for more Beethoven and Brahms as soon as she could put her violin under her chin again. In fact she played her way through recovery.

The most senior member of the Peninsula Symphony began her obsession with music at age 9, and she's learned a few things in the last 82 years. At the top of her list: Don't stop playing if you want to enjoy old age.

Growing up in San Francisco in a Jewish family that loved music, Libby was surrounded by musical stimulation. "All my cousins, everyone played," she remembers. One of her early memories is of Isaac Stern, Jewish violin virtuoso who was raised in the city. Stern died in 2001 at age 81.

"He used to play with my brother who was seven years younger, " says Libby, who now lives in Foster City. "I went to every concert he had. He was a prodigy. The first one was at the Fairmont Hotel. Was I impressed! My mother saw to it that I went to the concerts. She told me, 'If you practice, you may sound like that.'"

Her mother, whose family had brought her to California from Romania as a child, never had the time or money to play, but she made sure her daughter made the most of her talent.

She'll be playing with the Peninsula Symphony Friday and Saturday, May 23 and 24 at the San Mateo Performing Arts Center and at the Flint Center in Cupertino.

The symphony is not her only gig. Libby plays every day of the week. She recently played with one of her trios in the Jewish Home in San Francisco where her sister, Sylvia Elkins, lives.

Libby enjoys the hourlong performances for her peers at the Home, who soak up the classical pieces, and she finds the facility a congenial residence as well as concert venue.

"They have lots of activities, lots of music and performers — singers, piano players. They keep people happy and busy."

Part of what keeps Libby happy and busy is her family. She spends holidays with daughter Diane Marcus and her family.

"I often bring my violin, and if someone asks, you know me, I've got to play," says Libby, who goes to Peninsula Temple Beth El in San Mateo. "When you get older and you have something like this, that's when it pays off."

Sitting in her neat condominium where she lives with her two cats, she's interrupted several times by the phone. Once it's a string-playing crony. Another time it's her son wanting to chat.

She goes through her list of musical appointments: Monday nights with a trio including retired pediatrician Sam Leavitt. Wednesday nights she's played with Bill McKenna's Vintage Theater. The list includes string quartets, trios and duos. She plays in Golden Strings, a quartet that plays for weddings, funerals and the annual Chocolate Festival in Belmont.

"I play in pit orchestras, too. I just have to play. I don't know how you are supposed to feel when you are 90. I kind of brag about it now. A few years ago I didn't. I wanted to make myself younger."

Although much of her current playing is also a vehicle for socializing, she's always been serious about her music. She attended the San Francisco Conservatory of Music, studied with renowned teacher Kathleen Parlow and learned to sight-read anything on her music stand, from quartets to symphonies, without missing a downbeat.

When Libby married and moved to San Bernardino, "I didn't know how to do anything around the house," she confesses. Her late husband, Alexander, taught her to cook, but the details of homemaking didn't hold her interest long. She plunged into learning the family dress-shop business in San Bernardino.

After work, she scouted out every musical group in the Southern California area. She played at Redlands Bowl, in the San Bernardino Symphony and was concertmistress of the Riverside Symphony. She played during the Kol Nidre service at her synagogue in San Bernardino. Once a week, while her husband took care of the kids, she drove to Los Angeles and played chamber music with friends.

Later, they moved to the Long Beach area. When her husband became a stockbroker, she studied for her license and, herself, remained a stockbroker for 30 years.

Not that there haven't been setbacks. She learned to ride a bike at age 65 and thought it was "the greatest thing" until 10 years later, when she was hit by a car while crossing with a green light.

"I had three pelvic fractures. It took me about three years to learn to walk and function again," she says.

Although she had to give up her golf game, she could continue to play her violin.

About 10 years ago, she returned to the Bay Area. The adventures, she admits, have taken their toll. She has arthritis, and "you don't always feel good. Sure you pretend sometimes. No question."

Looking at her life, she says, "I feel lucky. It isn't anything I've done. I've eaten properly, mostly vegetables. I don't cook and I don't clean. I don't do windows. I'd rather do without other things and have someone else do that for me."

But when it comes to music, "I never say no. I get to play all the time. I have a lot of energy. I think it's because my life is wrapped up with music."