Youco began her studies in painting at an art college in Japan, where she ultimately became interested in fashion design. After graduating from art school, she relocated to London and studied at Central Saint Martins before transferring to the London College of Fashion. Her 2003 graduation collection received press from the Daily Telegraph, and garnered her a job offer from TOCCA LLC in New York. She relocated to NYC in 2003, and took on an assistant designer position at TOCCA, which she held for year and a half, before designing the entire collection under the direction of the owner. She left TOCCA after the S/S 2006 collection, and launched her own line 2006 fall, called YOUCO.