Always hard to tell with TV (some actors maintain a baby face for years, on the other hand, Gendry in Game of Thrones provoked me, the first time I saw it to say, "Gendry, you can't be Robert's bastard, you are clearly forty-three years old." But Penguin, at least, seems to be fairly young. Older than Bruce, certainly, but not likely to be ancient and decrepit by the time Bruce finishes his training. And an older Riddler works fairly well for me- he's always been about imposing an intellectual challenge rather than a physical one.