January 26th has always been the anniversary of the day in 1788 when Captain Arthur Phillip established the first colony of New South Wales.
The first fleet had already made landfall in Botany Bay a few days earlier but that area had been considered unsuitable.
There had already been several settlements established by Europeans since the 1600s but this was the first European colony.
By all means, commemorate Federation Day on the first of January. I do. But you can't change the date Captain (Governor) Phillip established the colony any more than you can change the date you were born.
It seems some have forgotten meanings and the events behind our holidays.

