For other purposes Tishri is the first month, making it one of four New Years listed in the Mishnah Rosh HaShanah.
The choice of Nisan to head the list of Hebrew months is because that was the month when the tribes of Israel became a people and set out on their journey through history.
We appreciate the logic in the choice of this month, but we often fail to notice that the command to place Nisan on a pedestal and celebrate the redemption of the Israelite slaves was given whilst they were still in Egypt in a state of bondage.
The Exodus event had not yet happened, but they were already told to celebrate it. It is not simply that the slavery was visibly winding down and the people’s release was inevitable.
The Torah was not just thinking pragmatically but spiritually. Its message was one of faith: “Know that God has heard your cries and will redeem you and protect you!”
It would be a terrible anticlimax if the time of bondage came to an end and the people were left to pick themselves up and fend for themselves.
There was a Divine promise: they would march boldly out of Egypt, cross the sea and move into the future with the Almighty smiling upon them and holding their hands.