Answer by taking a quote from the following article:

Frank Vincent Zappa (December 21, 1940 - December 4, 1993) was an American musician, composer, activist and filmmaker. His work is characterized by nonconformity, free-form improvisation, sound experiments, musical virtuosity, and satire of American culture. In a career spanning more than 30 years, Zappa composed rock, pop, jazz, jazz fusion, orchestral and musique concrete works, and produced almost all of the 60-plus albums that he released with his band the Mothers of Invention and as a solo artist. Zappa also directed feature-length films and music videos, and designed album covers.

Zappa was born on December 21, 1940 in Baltimore, Maryland. His mother, Rosemarie (nee Collimore) was of Italian (Neapolitan and Sicilian) and French ancestry; his father, whose name was anglicized to Francis Vincent Zappa, was an immigrant from Partinico, Sicily, with Greek and Arab ancestry.  Frank, the eldest of four children, was raised in an Italian-American household where Italian was often spoken by his grandparents. The family moved often because his father, a chemist and mathematician, worked in the defense industry. After a time in Florida in the 1940s, the family returned to Maryland, where Zappa's father worked at the Edgewood Arsenal chemical warfare facility of the Aberdeen Proving Ground. Due to their home's proximity to the arsenal, which stored mustard gas, gas masks were kept in the home in case of an accident. This had a profound effect on Zappa, and references to germs, germ warfare and the defense industry occur throughout his work.  Zappa was often sick as a child, suffering from asthma, earaches and sinus problems. A doctor treated his sinusitis by inserting a pellet of radium into each of Zappa's nostrils. At the time, little was known about the potential dangers of even small amounts of therapeutic radiation, and although it has since been claimed that nasal radium treatment has causal connections to cancer, no studies have provided significant enough evidence to confirm this.  Nasal imagery and references appear in his music and lyrics, as well as in the collage album covers created by his long-time collaborator Cal Schenkel. Zappa believed his childhood diseases might have been due to exposure to mustard gas, released by the nearby chemical warfare facility. His health worsened when he lived in Baltimore. In 1952, his family relocated for reasons of health. They next moved to Monterey, California, where his father taught metallurgy at the Naval Postgraduate School. They soon moved to Claremont, California, then to El Cajon, before finally settling in San Diego.

When did he get interested in music?