Here in this video you will learn about the calendar that was given to man in the Bible to live under. This is the same calendar that was used when Jesus was living on earth. It wasn't until 359 AD that it was changed. It was pre-calculated out ahead of time. This is not how the calendar is supposed to go. The calendar is supposed to be relied on God and cannot be predetermined. Please check out these verses to help understand what is the calendar. Also remember that some of the translations have translated Aviv incorrectly but the verses I will show you will be correct and you can always cross check with the hebrew.

Aviv:
Exodus 13:4, 23:15, 34:18; Deut 16:1; Lev 2:14, Numbers 10:10

New Moon:
Genesis 8:4-5 and 14; Colos 2:16-18; Exodus 12:2, 13:4; 2 Chron 31:7; Esther 3:7; 1 Kings 5:14; Lev 23:5; Isaiah 1:14, 66:23; Nehem 10:33; Ezra 10:17; Psalms 81:3; Amos 4:7, 8:5; Hosea 2:11; Ezekiel 45:17, 46:1; 2 Kings 4:23; 1 Samuel 20:5 and 24