Ironically, my chart started small.I agree completely. There will be a progression through the ages without a doubt (another reason I want to keep the list small). I also want the different types of dragons to feel different and not all be the same (I am looking at you MM).
It got bigger as I pondered how draconic life events would change how the dragons fight and what resources they have. For example, a dragon wouldn't get full sorcery until they settle down and start thinking inward. That doesn't happen until they hit the mature adult age That's when they stop caring about insults, reproduction, or shows of power, and start focusing on their legacy and hoard.