She said yes! Lily Collins announced her engagement to director Charlie McDowell via Instagram on Sept. 25. “I’ve been waiting my lifetime for you and I can’t wait to spend our lifetime together,” the actress, 31, captioned a sweet snap from the proposal. While Lily and Charlie, 37, are a relatively private couple, “they both come from showbiz families,” notes a source, “so the wedding is sure to be a glamorous affair.” Charlie’s mom Mary Steenburgen “absolutely adores Lily,” the source says, as does his stepdad, Ted Danson. Lily’s own father, Phil Collins, “hasn’t stopped singing since he heard the news,” adds the source, “Of course, nobody would be surprised if he performed at the reception.”…