I do not like cousin marriages in modern times, but I think they are kind of more difficult to avoid, and perhaps needed, with a small population (especially when each town has like 10 people, like in the game, hahahaha).
Also, about the heroes being "16", or the previous heroes being around "30" when their pictures look more like 70...
On this, my first time paying the game, I went Ayn's route. I noticed how the game mentions 15 years of peace before the game lets us control him. Then I see people saying how he was 15 years old. My mind then thinks that, if those 15 years start exactly the day of the wedding, then Ayn would be 14, not 15.
I also think (especially seeing how the PS III books mention him being 18 years old) that those years of peace started some years after the wedding. Maia/Marina was 16 when she got married, and she could definitely have kids then, but she could also have waited a few years. And the marriage must have helped bring the two kingdoms together, definitely, but there was still too much hate between the two people at that time. Getting used to the new status may have taken some time and hard work.
If the 18 years age can be taken as "official" (since it just appears in an art book), then Ayn was already 3 when the peace finally started.
And all the men who get married in the game were at least 18 (some of the girls got married younger, but I suppose that was also normal in medieval Europe, and it is still normal, even now, that the brides are younger than the grooms).
Edit: I guess I would need to know what the original Japanese text says. The English translation does mention Cille was a peaceful kingdom, even at the time of the wedding, then it mentions 15 years of peace, and then we start controlling Ayn.
