Rihanna won't be a legend. Stop

Britney is a pop music legend. But she's a musical icon.
Madonna released True Blue at the age of 28 so there you go.

Rihanna, Shakira, Beyonce, GaGa and Britney already are, I think...

MJ was already an veteran before he even hit his teenage years,an ICON tho,by age 25 THE LEGEND in every damn sens of the word only the KANG

This. I think some of the people being mentioned are legends now but before or by age 30?? nah. Mike's the only one of them that I know had been around for 20 years (which is my standard to be considered for this kind of status) by age 30.

The only way I will consider before age 30 is if the artist made a massive amount of impact and passed away beforehand.