I'm based in the Central time zone in the US. Which one of these should I create my supabase project in?

Zones are mostly just gonna affect your speed, so it doesn't entirely matter which one you pick. Whichever side of the US you're closer to is the one you'd wanna pick. If you're in the middle of Kansas then I guess just pick whichever one you want, the speeds will be about the same.

Okay sweet good to know