Album: Age Ain't Nothing But a Number (1994)

From the second she cooed "ooh, it's the L-I-Y-A-H" listeners couldn't tell whether Aaliyah was grown or just tryna be. Didn't matter. The lead single off her debut album, Age Aint Nuthin' But a Number-written and produced by (and featuring guest bars from) R. Kelly-was also Aaliyah's first number one, knocking Kellz's "Bump and Grind" from its 13-week perch on top of the R&B charts.

At the time, Aaliyah played coy with the media about her age and "Back & Forth" shows why she could. Instead of over-emoting like a child singer, Aaliyah's confident in singing about something basic—it's just a song about partying on a Friday night-and that takes an adult's restraint. In the video she's already armored in the tomboy style that would make her a Tommy Jeans model and icon to attitudinal girls everywhere. Seven months later Vibe published a copy of an Illinois marriage license purporting to show that Haughton was indeed married to her mentor, proving that in the music industry the word 'protégée' aint nothin' but a euphemism. —Elena Bergeron