his 2002 nationwide Đợi chờ trong cơn mưa concert tour, which marked her debut as an adult singer. In September 2003, Tiên signed up for the music competition Yo! Cùng ước mơ xanh and added two years to her age. The show ended with four winners—Tóc Tiên, Nam Cường, Minh Thư and Viết Thanh—joining a short-lived group, Yo! Band; its members later went on to have solo careers. Tiên began studying biology at Lê Hồng Phong High School, one of Vietnam's most prestigious high schools, in 2004. Although her grades were generally good until her graduation in 2007, they sometimes suffered due to her work schedule. The singer took vocal lessons at the city's conservatory and played for her district's volleyball team. She was the Most Notable Face in Người đẹp qua ảnh, a 2005 Fujifilm modeling contest, and was recognized for songs such as "Tuổi teen tóc mây", "Rock học trò" and "Cô bé tóc xù". Tiên made her acting debut when she was the first actress to portray doctor Đặng Thùy Trâm for a segment aired on the VTV3 talk show Người đương thời. She later participated in Tiếng hát truyền hình toàn quốc giải Sao Mai, her third singing competition; this surprised many since Tiên was an established performer at the time. "I came to the competition to prove myself, not to test my abilities," she said. One of eighteen Southern finalists, Tiên sang Đỗ Bảo's "Bài hát cho em" on 19 November 2005, live show but lost. Tiên contributed vocals to two tracks on Quốc Bảo's 2006 album V, including "Chung thân", the song that was later included in Ngọc Hiệp-directed short film Con rối. During an interview, the singer announced that an album was in the works and she would take a year off from singing to prepare for the national university-entrance examination. Tiên said several times that she wanted to be a doctor, with her singing career a "side job". Her mother scheduled the album's recording for the summer to ensure that her daughter could focus on studying. The singer released her debut album, Nụ cười nắng mai, in February 2007. After the July examination, Tiên was not admitted to her first-choice school, Ho Chi Minh City Medicine and Pharmacy University's Faculty of Medicine, and opted for the university's Faculty of Traditional Medicine. In May 2008, Tiên began co-hosting the fourth season of Bài