"It is my favorite week."
Translation:Es mi semana favorita.
Native speakers have told me (and even insisted) that "favorita" should go before the noun.
As in "Es mi favorita semana"? That doesn't make sense; it would be like saying "It's my week favorite" in English.
(I'm a native speaker).
This doesn't make sense. You can't describe an adjective with a noun, and you shouldn't put the noun before the adjective, or else native speakers will call you out on it.