If she ever does, it probably won’t be much of a choice! Dragons will only continue to progress into a Stage Three Wyrm if 1. they are incredibly, ridiculously bound to their obsession, or 2. they are continuously exposed to a very large amount of arcane radiation, generally more than their bodies are capable of venting (the glow around their eyes + source of their fire is basically a way to burn off excess energy).
Dragons that make their homes in more magically significant areas may go through this if they live long enough; dragons that intentionally hunt other magical creatures, or are frequently in arcane combat, are practically guaranteed to mutate further (if they survive their lifestyle). Linnae has a fairly high chance of it eventually happening because she travels with Augustine, who is naturally drawn to strong sources of magic to hunt.
She’d probs look a lot weirder than this if it happened, honestly–I should design it properly. This is a lil phoned in. Basically all bets are off when a dragon hits end stage, and they can get REALLY weird. Linnae’s pretty stable and starts off looking like a fairly classically styled dragon, so she might look a little more ‘normal’, but not by much.
Cold weather can be surprisingly fatal to Glutton Knights, since, y’know, their flesh is fused to their metal armor. Augustine was terribly unprepared for this and only survives their first winter because Linnae is a huge walking furnace. \