(CNN) -- The oldest daughter of the Austrian family portrayed in the 1965 film "The Sound of Music" died of heart failure Tuesday, a friend confirmed.

Agathe von Trapp, 97, was in a Gilchrist Hospice in Towson, Maryland, when she died, her friend Mary Louise Kane told CNN Thursday.

She fell ill November 9 and was moved on December 2 to the Gilchrist Hospice, said Kane, who ran a kindergarten with von Trapp in Glyndon, Maryland.

The 16-year-old Liesl von Trapp character in the movie was based on Agathe, but the writer and director took great artistic license with the portrayal, Kane said.

"(Von Trapp) was nothing at all like the Liesl character," Kane said. "She was a very private person and a bit shy. She didn't like being in the limelight at all."

Contrary to the movie, she was not the oldest of the von Trapp family. An older brother was made younger in the script.

"Liesl was a made-up character," Kane said. "I never thought of her being Agathe because they were too unlike."

Four siblings survive, including Maria, 96, who lives in Vermont, Kane said. Three half-siblings still alive are Rosemarie, Eleonore, and Johannes, she said.

The von Trapp family fled Austria in 1938 to escape Nazi persecution. They toured the United States as the Trapp Family Singers after World War II.

Agathe von Trapp wrote her life story in a book published in 2003 and republished last September, Kane said.

"She was hoping to do some book signings," Kane said. "She did enjoy the book signings because people would come and tell her how much they enjoyed her concerts."

Kane is hoping to hold a memorial service for her friend on March 12, which would have been Agathe von Trapp's 98th birthday.