I can't recall the details, but Christmas is on the wrong date and Easter (a pagan fertility holiday) was propagated by the Catholics instead of Passover. I stand to be corrected on this.
You are actually entirely correct and need not be corrected.
1 - Are you Christian?
2 - What denomination teaches these things you seem to recall?
3 - Do you celebrate Easter and Christmas?
You wrote, “Easter (a pagan fertility holiday) was propagated by the Catholics instead of Passover.”
Jesus gave us a New Covenant, so Easter is the celebration of the Resurrection of the Lord, the triumph of Jesus over the grave. Surely you, as a Christian, know that. It is true that Easter practices with dyed egg, bunnies, etc. are borrowed from earlier spring festivals dating back to pagan times. But with the resurrection, we are called to a new ‘spring’ so to speak, and should not deny the significance of the day due to some pagan myths mixing into the day’s celebration.
Secondly, you admit that the Catholic church was the entity that began celebration of the Resurrection of the Lord - which takes us back to the time of the Apostles. Of course the first Christians celebrated Jesus’s Resurrection. We are into the New Covenant of God with His people. Jesus’s Last Supper, and His Crucifixion are not the end to his story, for His triumphal emergence from death to life on that Holy morning is celebrated now as a Christian holiday which Europeans called Easter (Ostertag in German) because it indicates the dawn of a new day when the sun rises in the east.