Lulu had her first hit “Shout” at 15, and is best known to American audiences for 1967’s “To Sir With Love” from the film of the same title, but now at 64, she’s ready to take Manhattan by storm. She’s performing at B.B. King Blues Club on Saturday with a band that includes David Letterman maestro Paul Shaffer. She says of acts that have endured: “The Stones, Elton, McCartney and myself have been around forever. Why are we still doing it? Even though the Stones are being paid a gazillion, they started doing this because they loved the music.” She’s been married to Bee Gee Maurice Gibb and celeb hairdresser John Frieda, and says of her long career, “Being in the limelight . . . you have to pay the price. There’s been heartache, ups and downs. I can relate to any young person starting and the pitfalls they face. In the end, I was one of the lucky ones.” The London-based singer also has a skin-care business and will appear on QVC on March 28.