On thing I've noticed with computer animation is that it has a hard time making old people look like they are not caricatures of old people. This is especially true when working with a pre-made character builder. You can see this with characters like Varis, who hovers on the edge of being a caricature. I can't take him seriously, and a lot of that is due to his face being so fake compared to the other characters. He looks hilariously fake.

However, age isn't just what people look like, it's also how people act. Edmont de Fortemps feels older not just because his face does look older then most characters. He also behaves like he's been around for a while. He knows how Ishgard works and he's got experience that people like Aymeric don't have because of it. I can believe that he's spent forty years as the head of House Fortemps.

Kinda like it's pretty easy to believe Shadowhunter has been taking command of battlefields for a long time. And laying out options for people in ways that make his ideas be the ones people go with.