I thought the calendar difference had more to do with the reckoning of days, whether a day ends and begins at sundown or at sunrise?
The more important facts are that Jesus died on a Friday and rose on Sunday morning. There are Christians out there trying to refute that, because they try to force the events into an exact literal 3 days and 3 nights (72 hours) in the grave, mutilating the bulk of the accounts to fit one allegorical mention of Christ’s time in the earth being like Jonah’s time in the whale.
What’s more important, thematically, is that Jesus had to die at the time the Paschal lamb was being sacrificed, had to be taken down with some haste before the Sabbath where no one could work (in order to have the lance and not the broken bones so that he would be an unblemished lamb, and in order that the women would have to return Sunday morning to finish treating the body). And then he had to remain in the tomb on the day of rest, as we all rest and await, our lamps lit like the virgins at vigil, faithful in expectation even as we feel abandoned like Christ felt abandoned.
For Jesus, the New Adam who makes all things new, had to bring about his New Creation by his resurrection on the First Day of the week, not the last, when God rested. Thus, we celebrate the New Creation just as God began his creation on the first day.
Themes like these are important witnesses to the divine authorship and action of God, and aids to our understanding and relationship with him. If the timing of things does not violate the truth embodied in the message, then it is more incidental concern.
It’s worth asking.