I have written numerous Posts on the topic of end time theology over the last few years, primarily because it is such an intriguing thing to speculate on, whether we are in the final days of our current church age which began when Jesus Christ ascended to heaven approximately 2000 years ago.
The reason that I believed that 2019 was the end of the age originated from a Biblical Chronology website I found a few years ago, which is now no longer online, but can be found in the web archives. I have posted below, the archived links for anybody who is interested. I contacted Ron Conte who originally put up the website, and received a reply today from Ron advising that he took down the site himself. Anybody who wants to purchase any of Ron's ebooks can find them at http://www.catholicplanet.com/books.htm
http://web.archive.org/web/20180806222026/http://biblicalchronology.com/
http://web.archive.org/web/20180806222026/http://biblicalchronology.com/census.htm
http://web.archive.org/web/20180806222026/http://biblicalchronology.com/tiberius.htm
Those links, and others on that site, explained that according to the research done by Ron back in 2003, Jesus Christ was not born 2019 years ago in the year 1 BC, as one would think from our current calendar, but in fact was born in 15 BC. You can read through the information on the above pages for explanations on why Ron believes this is the case. For the short version, Ron has another website which has a nice simple explanation of how this all works:
https://ronconte.com/2012/12/03/the-date-of-christs-birth-and-the-christian-calendar/
To cut a long story short, if Jesus was born on November 25, 15 BC as Ron claims on another website he owns, then if we count 33 years from there we find that Jesus 33rd birthday was on November 25, 19 AD.
http://www.catholicplanet.com/dates/
The reason that I miscalculated the year of Jesus death, resurrection and ascension, is because, unlike your life in the year 2019, because of the peculiarities of our calendar, there was a year missing in the lives of everyone who lived in the AD/BC years, that being the year 0, which did not exist. We go straight from 1 BC to 1 AD. To make this clear, I will lay out the years of Jesus life below so you can see for yourself.
BC
15 Jesus birth
14 1st birthday
13 2nd birthday
12 3rd birthday
11 4th birthday
10 5th birthday
9 6th birthday
8 7th birthday
7 8th birthday
6 9th birthday
5 10th birthday
4 11th birthday
3 12th birthday
2 13th birthday
1 14th birthday
AD - missing year
1 15th birthday
2 16th birthday
3 17th birthday
4 18th birthday
5 19th birthday
6 20th birthday
7 21st birthday
8 22nd birthday
9 23rd birthday
10 24th birthday
11 25th birthday
12 26th birthday
13 27th birthday
14 28th birthday
15 29th birthday
16 30th birthday
17 31st birthday
18 32nd birthday
19 33rd birthday
20 Ascension Day, 40 days after the Feast of First Fruits
So the upshot of all this, is that if we go by the Millennial Day theory which states that the church age will last 2000 years, then the end of the age will be sometime in May 2020, but not necessarily on the day celebrated by the church, which will be Thursday May 21, 2020. I have some issues with the way this is calculated, as according to my reckoning, Jesus rose from the dead on a Monday, three days after Passover on Friday, so if Ascension Day is 40 days later it should be on a Saturday not a Thursday. (to prove this, just add 42 days or 6 weeks, then go back 2 days - 2 days before Monday is Saturday). But I am not fussed about the day or the hour, so we'll cross that bridge in 2020 when we come to it.