Revelation is more about present hope than a future calendar

1 Then one of the seven angels who had the seven bowls came and said to me, “Come, I will show you the judgment of the great prostitute who is seated on many waters, 2 with whom the kings of the earth have committed sexual immorality, and with the wine of whose sexual immorality the dwellers on earth have become drunk.” 3 And he carried me away in the Spirit into a wilderness, and I saw a woman sitting on a scarlet beast that was full of blasphemous names, and it had seven heads and ten horns. 4 The woman was arrayed in purple and scarlet, and adorned with gold and jewels and pearls, holding in her hand a golden cup full of abominations and the impurities of her sexual immorality. 5 And on her forehead was written a name of mystery: “Babylon the great, mother of prostitutes and of earth's abominations.” 6 And I saw the woman, drunk with the blood of the saints, the blood of the martyrs of Jesus.
Revelation 17:1-6

14 They will make war on the Lamb, and the Lamb will conquer them, for he is Lord of lords and King of kings, and those with him are called and chosen and faithful.”15 And the angel said to me, “The waters that you saw, where the prostitute is seated, are peoples and multitudes and nations and languages. 16 And the ten horns that you saw, they and the beast will hate the prostitute. They will make her desolate and naked, and devour her flesh and burn her up with fire, 17 for God has put it into their hearts to carry out his purpose by being of one mind and handing over their royal power to the beast, until the words of God are fulfilled. 18 And the woman that you saw is the great city that has dominion over the kings of the earth.”
Revelation 17:14-18

1 After this I saw another angel coming down from heaven, having great authority, and the earth was made bright with his glory. 2 And he called out with a mighty voice,“Fallen, fallen is Babylon the great! She has become a dwelling place for demons, a haunt for every unclean spirit, a haunt for every unclean bird, a haunt for every unclean and detestable beast. 3 For all nations have drunk the wine of the passion of her sexual immorality, and the kings of the earth have committed immorality with her, and the merchants of the earth have grown rich from the power of her luxurious living.” 4 Then I heard another voice from heaven saying,“Come out of her, my people, lest you take part in her sins, lest you share in her plagues; 5 for her sins are heaped high as heaven, and God has remembered her iniquities.
Revelation 18:1-5

Defining Babylon

The Attraction of Babylon

The Call Out of Babylon

The End of Babylon