Ai was born in Los Angeles in 1981. Her father was Japanese and her mother was half Italian-American and half Japanese. She moved to Kagoshima in Japan when she was 4, and went to elementary school and junior high school in Japan.  Ai was motivated to become a singer in her early teens, after singing at a cousin's wedding, having many people ask her if she wanted to be a professional singer, and hearing a gospel performance at the First African Methodist Episcopal Church of Los Angeles in 1993. After graduating from junior high school in Japan, Ai returned to Los Angeles for high school, enrolling at Glendale High School, however found high school difficult due to never formally studying English. After making it through the audition process, she switched to the Los Angeles County High School for the Arts, majoring in ballet. She became a member of the school's gospel choir. In 1998, she performed in a gospel choir at a Mary J. Blige concert at the Universal Amphitheatre, performing of "A Dream." In the same year, she appeared as a dancer in the music video for Janet Jackson's song "Go Deep."  In 1999, she joined an Asian girl group called SX4, who were produced by George Brown of Kool & the Gang. Ai was a member of the group for two years, and later in 1999 the group were offered a record label deal. While on her summer holiday in Kagoshima, she performed Monica's "For You I Will" on a local radio station, which led to her being scouted by BMG Japan. She decided to take the offer, and after leaving SX4 and graduating from high school in June 2000, moved to Tokyo and debuted as a musician later in 2000.

Answer this question "What did she do in tokyo" by extracting the answer from the text above.
debuted as a musician