Debut Era was a period in Mariah's career spanning from 1990-1991.
The period is marked by the release of Mariah's first studio album, Mariah Carey.
Mariah Carey Wiki recognizes Debut Era as beginning on May 15, 1990 and ending on July 30, 1991
Background
On May 15, 1990, Mariah released the first single "Vision of Love" from her album Mariah Carey. The release of this song marked the beginning of Debut Era. On July 30, 1991, Mariah was spotted at the Z100 8th Anniversary Party at the Palladium in New York, NY. This appearance marked the end of Debut Era.