His age isn't the issue, it's that he really not had much actual experience of any kind going into politics even though he was in his forties. A bit of teaching here, a bit of snowboard instruction there, but no real career experience. His father was a bit like that, too. I am a bit sour on career politicians (you know, the ones who enter politics right out of university and nothing but), but at least someone who has had a stable, professional, progressive career of some kind where they might have learned some skills at working with, and managing, people. Law is the traditional one since it also makes one familiar with the legal system and how laws are made and interpreted but even something like a grocery clerk who worked their up to store manager or something would be preferable to someone who just kind of flits from thing to thing. Trump at least had decades in the real estate and property development business, even if his reputation and actual ability there seems to have been bit dubious.