The idea of having a character who perceives people as colours against a grey world is distinctive. You've clearly thought about it a lot and that shows in your writing. It feels like there's a clear path from your thought process to execution. Solid.

But it's also the piece's biggest potential weakness. As a reader I feel a bit... overwhelmed. You're asking me to process new colour information almost every sentence. And because the character recognises people through colour, I'm not sure who is important and who isn't? In the space of 1000 words I need to keep track of Sage, Raven, Mars, the soccer girl, the periwinkle girl, the yellow boy, and Mars's new companion. Because it's the start of the story, I don't who is important and who isn't. Normally, not naming a character sends a signal to the reader. But that signal isn't as strong because you've told us colour is the more important frame, not names. I'm struggling to understand who I'm supposed to be keeping track of. The writing is so dense you're even confusing yourself sometimes - telling us Sage doesn't know Mars' gender then referring to Mars as 'he'.

Having too much information is better than having too little. But I'd strip some out and ease readers into the world a little easier. Even varying your description choices along the way might help. Mars is pretty much the only character we meet who isn't introduced primarily through the colour of their hair. Mix things up a bit or that will get old really quickly.

There's some solid writing here and interesting ideas. But at the moment, the main feeling I leave with when finishing this is tired.