29 is not old for a keeper. I thought he was older to be honest. He's been around for years. Made his debut in the 99-00 season. He was 19. Played 47 games that season aswell, which is unheard of for a GK that young.
My only problem with Casillas is his height. Quite short for how I like my GK's. No doubt about his goalkeeping ability though. Top class GK who deserves to play behind a solid back 4.