Your whole argument here rests on putting the Psalm to music and then getting creative with how they relate to each other because you think it fits better. I find this very unconvincing.
It may interest you to know that scripture in its original language has a poetic structure that flows through nearly every passage - complete with rhythmic word puns and rhymes. It's something we lose when translated into other languages like English.
So literary devices like what's in Psalm 81 aren't the exception, but the rule. In fact, most of the psalms written by King David are poetic.
If one were to go by the first visible crescent this month, it is March 19, at 3.1%. Since division of days are reckoned from evening to evening, New Moon day (the daylight portion) is March 20th. Day 1 of new lunar month. Counting to 14 places Passover on the evening of the 2nd of April, which is a Monday.
You can go back and redefine your New Moon even two days when there isn't one. Even if you do this, at the very earliest passover would fall on a Saturday.
Yes If you mean "Passover" as in "the feast of unleavened bread", then that would just make next Monday the holiday this year. But if you mean "Passover" as in "the preparation day before the feast", then the preparation would fall on the prior work day: this coming Sunday this year...meaning the Day of First Fruits will be on the following Sunday.
With every new day, new month and new year being determined by sight and not by calculation it means the feasts are never guaranteed to be on the same day of the week each year, teaching us to humble ourselves and follow God's lead for all time, all the time.
Anyway, for those who insist a New Moon is Dark or first visible crescent, you can believe that, but count 14 days and you'll wind up later than Friday the 30th, the day you are celebrating passover. .
Agreed, we are to follow our Father's calendar as instructed in scripture not man's calendar...but as you know, it was prophesied in Daniel 7:25 that the "little horn" would seek to change times (calendar) and laws (commandments) as it persecutes God's people, and has indeed done so. So it won't match the Gregorian or Jewish calendar every year.
But yes, this Friday wouldn't be considered the 30th of the month if we followed the sighting, but properly the 12th of the month.