Everything here seems right on so far, but whether it's truly the Astral Era or not, as of now, is a common question I've seen. The leaders of the companies might be ready to declare it an Astral Era because we beat Ultima Weapon, but all we've really succeeded in doing so far is de-possessing Thancred and taking the XIVth Legion out of Lahabrea's manipulation network. The true cause of the Umbral Era is still out there. Bahamut is undefeated. Odin is loose. The primals are still being summoned. The aether is still in chaos. Even during their declaration of the Seventh Astral Era is interrupted by a primal roar.

I'm going to take a risk here and say that it's still 5 Seventh Umbral Era and they were just wrong.