Looks interesting, though the storytelling could use some polish.
I mean, "How did you know I was a witch?" when she's wearing stereotypical witch clothes is an incredibly forced way of introducing her witch brooch. Especially considering she's been wearing it for 2 years already.
And that "Flying in the sky is encouraged" sign is just bullshit. If you build roads and streets, you encourage walking. If the streets are too crowded, you'll naturally take to the air. There's absolutely no point in those signs, just as there's no point in "Driving in cars is encouraged" signs in our world.
Other than that, it appears to be quite enjoyable for a first chapter. Hopefully it stays that way.
@Aoitenshi
Nike's actually the Greek Goddess of victory. It is neither a coincidence nor a secret that the shoe brand company named itself after her.
I think we need more stories about the real Nike, so people are less likely to attribute her name to some shoe brand.