Why would we assume that?
I don’t think I wrote that - “the terminal generation started in 1948”.
Well, in 1948 Israel became a Nation again after 1900 and some years of being “not a nation”.
We know that the literal nation of Israel is a very big key to God’s timetable and His Plan - because He chose and called Israel into being to be His People, His Nation.
It’s too much to cover here but I would encourage you to, for instance, go find some of the excellent resources available about Israel - the modern nation of Israel - and how its establishment again as a nation in its “homeland” in 1948 really started the “final days” countdown in earnest.
John Hagee Ministries has probably the most complete information about this available.
God bless!