Florence Henderson, 1st Ld-Writethru Eds: Henderson's star is at 7070 Hollywood Blvd.; Cross street is Sycamore HOLLYWOOD (CNS) - Actress-singer Florence Henderson celebrated her birthday and Valentine's Day today by receiving a star on the Hollywood Walk of Fame. "If you knew how long I've wanted one, you just wouldn't believe it," she quipped. Henderson, whose career encompasses three decades of work on stage, screen and television, is known around the world as Carol Brady for her role on the 1970s sitcom "The Brady Bunch." Chris Knight, who played her son, Peter Brady, and "Brady Bunch" creator Sherwood Schwartz were on hand for the ceremony. "I'm so happy for her, I'm proud of her," Knight said. "I knew it was going to happen though." The Indiana native, who turned 62 today, got a "Happy Birthday" serenade from singer Marilyn Horne and Jim Nabors. CNS-02-14-1996 17:08