Fwiw, the program I sent the link to addresses the points you mentioned with Scripture, names and dates.
Does it matter? Who is the Judge of such things?
Personally, I think its fascinating how many different opinions we all have and the justifications we have for them, simply to understand and explain to ourselves the One who was, is and shall be. And we each know we are correct!
Even with Easter, we have 2 separate days to celebrate!
And just look at what we do with Christmas and the different calendars for that day! Wow...
As to what calendar, what days to celebrate what on, etc., it doesn't matter as much as you think it does. Christians are free to decide many things for themselves and not get caught up in disputable matters, endless genealogies, irreverent and silly myths and controversial speculations. They are time wasters and only muddy the waters. People behind cults often get newbies caught up in such things in order to make them question everything they may know and to sound like they have all the answers. Most times, they really don't.
My pastor often said we should remember that the main thing is to keep the main thing the main thing. The main thing is Jesus Christ who saves us by His sinless shed blood because of the grace, mercy and love of God. He offers to us eternal life through faith alone and not on the basis of what we do to earn or deserve it. Get that part settled in your heart and then let the Lord lead you from there. Ask Him to lead you to a Christian fellowship where you can meet with others to worship and learn about the Christian faith. It will help build you up and strengthen your faith. We all start out as babies in Christ and we need the "milk" at first. As we mature in the Lord, stronger "meat" can be tolerated. You should get the basics first. I've been a Christian for 50 years now and I can see the progression in my life as my faith has matured. I hardly know it all, but I have never lost my love of studying the word and seeing how God is working in my life to sanctify (set apart) me and conform me into being more like Christ. I know that I am going to heaven when I die - without a shadow of a doubt - and I rejoice in God my Savior. I will be praying for you to know that same assurance. I'll leave you with one of my favorite sayings and hope you believe it and take it to heart. I know it is truthful: