Everyone believes a spiritual doctrine either because of a preconceived idea (they grew up believing it) or because they studied and accepted it as a new truth. All truth is partial. It unfolds as one is ready for more. Further light is revealed as you are ready to accept.
Anyone who thinks they have ALL truth is beyond the working of Yahweh's Spirit.
Isaiah 55:6-9
Seek ye יהוה [Yahweh, our god] while he may be found, call ye upon him while he is near: Let the wicked forsake his way, and the unrighteous man his thoughts: and let him return unto יהוה [Yahweh], and he will have mercy upon him; and to our Elohim, for he will abundantly pardon. For my thoughts are not your thoughts, neither are your ways my ways, saith יהוה [Yahweh]. For as the heavens are higher than the earth, so are my ways higher than your ways, and my thoughts than your thoughts.
The first requirement for acceptance of new truth is acknowledgment that you may not currently possess all truth. Next, you need to remain impressionable and open to the Spirit's leading.
As you start to study the truth of Yahweh's time, you will probably pass through several stages (at least I did).
First, you will ridicule the idea and think it is foolishness.
This is time to remember that Yahweh's ways are not ours.
But if the Spirit is working with you on this subject, something will make you curious. You will keep being drawn to re-examine this subject.
It is a factual truth that Daniel told us that Satan's beast would think to change times, and a different calendar would certainly qualify. What if there is something to it all?
After further study, it will start to seem vaguely reasonable. After all, there are those pesky Bible texts about "new moon days". What's with that if it's all fiction?
Other's will grasp and accept it immediately, while some aren't ready at all. If you aren't ready, I would ask you to put it aside for a while, but not reject it outright until completely proven (or disproven) to yourself.
Eventually, you may be convicted of the truth of Yahweh's creation of time and wonder how you questioned it previously.
If you are ready to accept this truth, this study will attempt to help you implement it in your life. But be forewarned, it may be difficult to follow Yahweh. Many gave their lives to follow Him.