What year is it? <spoilers>

[Enkidoh]

Well, considering the Grand Company leaders are also the heads of state of the respective nations they represent, then yes, they would have that authority to declare whatever year it is.

Also I made a thread a while ago in the old forum which is now archived on this very subject (calender/day/year nomenclature) and from what I remember, is that an Umbral Era only lasts as long as whatever caused it in the first place is still causing devastation.

Therefore, because the Seventh Umbral Era was caused by Dalamud's fall and Bahamut's rampage, it led to a lot of speculation that ARR is really already in the Seventh Astral Era (essentially, the game would be set in the year 5, 7th AE as Bahamut has disappeared and Eorzea is technically recovering.

But, due to the fact that with the Primals still being active, the Empire not quitting their advance into Eorzea and the Ascians running around with their evil schemes, some consider the 7th Umbral Era to still be current (and the early comments by the leaders of the three nations in fact still refer to the 7th Umbral Era as being current). So therefore, the general belief would be, that ARR takes place in the year 5, 7th UE.