Mochida made her debut as a baby in an advertisement for diapers as her mom hoped she would enter the entertainment business. In 1991, at the age of 13, she joined the eight-member girl group The Kuro Buta All-Stars. Though not successful, the experience convinced her to record a two track demo, featuring the two songs, "Mouichido" (The Kuro Buta All-Stars) and a cover song from 1970s/80s singer-songwriter Mariya Takeuchi.