Many Pacquiao is older than Thurman is still young, but age doesn't matter when its comes to boxing fight and Pacman is always prepared for his game no matter what he do everything like practicing. So, I think he can do it. Especially to win the fight rather.
Pacman is a successful guy on his career in boxing as well as being a senator of his motherland Philippines. Even if he didn't make it to winning legacy on winning for Thurman, that not a problem with him. He's a one of the top paid fighter on this fight, I guess his preparation is long enough to perform the fight that will not disappoint everybody who been following his career eversince he was still an amateur fighter.