@Background Pony #F313
Not the vacation episode, the most recent one shown in the US - the Summer Sun Celebration episode. Twilight uses the amulet there.
@Copper Knight
I’d interpreted that as a short term solution, just during their vacation. Admittedly, I don’t think anything definite was said either way. (If it was addressed in the Dutch episodes, I wouldn’t know; I’m looking at spoilers but haven’t watched them.)
@Background Pony #F313
Uh, did you miss the Summer Sunset Festival? Twilight’s using an amulet infused with some of their power to move the sun and moon.
@Background Pony #8710
I like to toy with idea that Equestria is saturated with a type of cosmic-radioactive energy that augments one’s abilities as well as slows the aging process.
Imagine thinking they’ll make a unique model for Twilight in the last episode of the show when 90% of ponies, including the main characters, use the same body model with color changes and added details. With that consideration, Twilight looks unique enough.
I think Twilight and the Mane Six as being about 40-45 in this last chapter, but, that said, who cares: without an official age, it’s up to everybody’s headcanon.
I still think that celestia was cursed by using the elements to banishing NM and while she was in the moon she did not age, but once the return and twilight took the elements, that magic was gone.