@Antonyourknee
That actually makes some sense. Chrysalis has lived a long time herself. I feel like immortality is a lot more common in Equestria than I thought.

@Wayneponeth
I would think only changeling Royalty would be Immortal, having the necessary Magical ability, just like the pony Princesses. Chrysalis was implied to be long lived with at least a few centuries as Queendom.

I would imagine reformed changelings would live longer as well than their original black clad counterparts.

Not gonna lie, I’ve always wondered why that isn’t talked about as much.

Spike: “…and that’s how I saved Thorax just by singing a song.”
Luster: “Huh? Uh… Is not that I doesn’t believe Spike, but… Really? A song?”
Thorax: “Well, yeah. I still can’t believe it myself even after all those years. Who could have thought that a dragon from any creature in Equestria would manages to protect a changeling?”
Luster: “Not me! Oh. Uh, I mean as a old changeling.”
Thorax: “That’s quite alright. No offense taken.”
Flurry: “I barely remember how that happened, but I do remember two things about Thorax from back then: how kind he was and…” She giggled.
Thorax: “Huh? What?”
Flurry: “His tongue.”
Thorax: “Huh? M-my tongue? What about it?”
Flurry: “Well, it was funny and bizarre.”
Luster: “Really? Can you show it to me, Thorax?”
Thorax: “W-what? No!”
Spike: “Come on Luster. Leave him alone. He’s too shy on that matter.”
Thorax: “I am not!”
Spike: “Ok. Show it to her then.”
Thorax: “B-b-but pulling his tongue to anycreature is known to be rude.”
Spike: “See Luster?”
Thorax: “H-hey!” Flurry was laughing.

Even if Thorax was old, couldn’t he just simply transform into a younger shape?

This makes me wonder how changeling age works. Maybe Thorax is immortal too. What do changelings look like when they’re old?

Thorax still looking good although he must be getting old by then.