Spears became an international pop culture icon immediately after launching her recording career. "Rolling Stone" magazine wrote: "One of the most controversial and successful female vocalists of the 21st century," she "spearheaded the rise of post-millennial teen pop ... Spears early on cultivated a mixture of innocence and experience that broke the bank". She is listed by the "Guinness World Records" as having the "Best-selling album by a teenage solo artist". Melissa Ruggieri of the "Richmond Times-Dispatch" reported, "She's also marked for being the best-selling teenage artist. Before she turned 20 in 2001, Spears sold more than 25 million albums worldwide". Barbara Ellen of "The Observer" has reported: "Spears is famously one of the 'oldest' teenagers pop has ever produced, almost middle aged in terms of focus and determination. Many 19-year-olds haven't even started working by that age, whereas Britney, a former Mouseketeer, was that most unusual and volatile of American phenomena — a child with a full-time career. While other little girls were putting posters on their walls, Britney was wanting to be the poster on the wall. Whereas other children develop at their own pace, Britney was developing at a pace set by the ferociously competitive American entertainment industry". "...Baby One More Time" is Spears' most successful album to date, with worldwide sales of 27 million copies, and also the best-selling album by a teenage solo artist.