To me, this is where the disconnect is. Israel reigned as an independent country during the Hasmonean Dynasty. Why didn't this start the countdown?
The "countdown" began with the prophecy in Daniel 9:24-27 (Daniel's 70 Weeks prophecy):
Daniel 9:24 Seventy weeks are determined upon thy people and upon thy holy city, to finish the transgression, and to make an end of sins, and to make reconciliation for iniquity, and to bring in everlasting righteousness, and to seal up the vision and prophecy, and to anoint the most Holy.
Daniel 9:25 Know therefore and understand, that
from the going forth of the commandment to restore and to build Jerusalem unto the Messiah the Prince shall be seven weeks, and threescore and two weeks: the street shall be built again, and the wall, even in troublous times.
Daniel 9:26 And after threescore and two weeks shall Messiah be cut off, but not for himself: and the people of the prince that shall come shall destroy the city and the sanctuary; and the end thereof shall be with a flood, and unto the end of the war desolations are determined.
Daniel 9:27 And he shall confirm the covenant with many for one week: and in the midst of the week he shall cause the sacrifice and the oblation to cease, and for the overspreading of abominations he shall make it desolate, even until the consummation, and that determined shall be poured upon the desolate.
This prophecy describes
God's time schedule for the completion of His promises to the nation Israel. Israel is on God's time schedule, not ours.
Countdown begins in verse 25
"from the going forth of the commandment to restore and to build Jerusalem unto the Messiah the Prince..."
Nehemiah 2:1 And it came to pass in the month Nisan, in the twentieth year of Artaxerxes the king, that wine was before him: and I took up the wine, and gave it unto the king. Now I had not been beforetime sad in his presence.
Nehemiah 2:3 And said unto the king, Let the king live for ever: why should not my countenance be sad, when the city, the place of my fathers' sepulchres, lieth waste, and the gates thereof are consumed with fire?
Nehemiah 2:5 And I said unto the king, If it please the king, and if thy servant have found favour in thy sight, that thou wouldest send me unto Judah, unto the city of my fathers' sepulchres, that I may build it.
Nehemiah 2:6 And the king said unto me, (the queen also sitting by him,) For how long shall thy journey be? and when wilt thou return? So it pleased the king to send me; and I set him a time.
Nehemiah 2:8 And a letter unto Asaph the keeper of the king's forest, that he may give me timber to make beams for the gates of the palace which appertained to the house, and for the wall of the city, and for the house that I shall enter into. And the king granted me, according to the good hand of my God upon me.