“Do I have a favourite song by Whitney?” Mariah Carey ponders the question politely for a good five seconds. “To be honest,” she says, “I can't think of one.” And, anticipating further questions related to her oft-quoted vocal similarities with America's incumbent soul queen Whitney Houston, she is quick to add: “Anyway, I'm a songwriter. She's not.” It's a rare snipe from Carey, who otherwise radiates the kind of warmth and charm that comes from being 21, disarmingly sexy and phenomenally successful. “I guess I have been rather busy lately,” she sighs, tucking her knees under her chin. All that hard work has paid off Stateside in the form of five consecutive Number Ones (including “Emotions” and “Vision Of Love”), two Grammys, three Soul Train awards, and the fact that she is being hailed as the most stunning discovery since Aretha Franklin. Carey may only be 21, but success has been a long time coming. From the age of four she was taking singing lessons with her mother Patricia, a former soprano with the New York Opera; soon she was convinced she could make it too. It was this certainty that kept her going through a succession of dead-end waitressing jobs when she was still in her teens. “I remember looking at all these women who were twice my age working in the restaurants, and thinking, ‘If you don't want to end up like them, quit smoking, save your voice, and get out.’ ” She got out, but now prefers to stay in, swanning around her Manhattan apartment in hip-hugging Alaia, tending to her Doberman puppy. She eschews men (claiming she doesn't have time for them), choosing to spend what little free time she has practising harmonics and plotting the future.