Steve Martin would’ve been a “lousy father” if he’d had a child any earlier than he did. The 78-year-old actor has 11-year-old Mary with wife Anne Stringfield and explained that by becoming a dad in his late sixties, he avoided having to give his attention over to his career. He told Closer US: “I think if I’d had a child earlier, I would have been a lousy father because I would have misplaced my attention on my career. Now I’m just hanging around the house playing with [my daughter]. It’s great.” The ‘Trains, Planes and Automobiles’ star has opened up on his like like never before in the new …