Totally Nyx

Interesting question, since there's a few different ways to look at it. Age by technical birth date via the ritual that created her or age she appears to be, since she was born as a filly who looked to be more than a few years old already.  It also depends at what point in the story, like how old is she after season 10 ended?

I'm going with young adult. She was a little filly still going to school almost 10 years ago.

I would say approximate age really, because let's say she was like 8 at the age of the ritual, so yea young adult makes sense at this time. But it is pretty confusing since she technically was born at the point of creation so can be argued to be just about 10 years old or so. Well I guess we better ask Twilight 

Season 10??? Thought there was only 9 seasons. Either that or my mind is going senile

Oh, season 9. Woops.

It's so hard to get Nyx's age right. I was gonna make her character sheet for the new role playing system, but realized I need to do more research.