Olivia Rodrigo sells out the Cosmopolitan in Strip headlining debut John Katsilometes, Las Vegas Review-Journal · May 22, 2022 at 12:18 pm Olivia Rodrigo began a song introduction Friday night with, “Years ago, when I was 16 years old …” Wait a second. “Years ago, when I was 16 years old,” is something I would say. Because it was so many years ago. Rodrigo is only 19, but she’s waxing nostalgic of those days of yore, in 2019. At the time, Rodrigo was starring as Nini Salazar-Roberts on “High School Musical: The Series.” That’s when she penned the song she was about to sing, “All I Want.” That was among the songs the sold-out crowd could recite exactly. Actually, the crowd knew every word to every song Rodrigo performed.