Thread:Kingdomhearts12/@comment-22439-20141004003807/@comment-24199126-20141222142341

I can't give you a definite answer, but if I had to speculate, it could be because planning a coronation takes awhile, and as such, it was a few months late.

Also, in reality, many monarchs have two birthdays because celebration in winter can be marred by bad weather, so royals born in winter will have their actual birthday and an official one in summer to make it easier to celebrate.