You’ve said that the first specific sign Jesus gave to His disciples concerning His coming is in Matt. 24:15, the Abomination of Desolation. Why then do you conclude that the first sign of the End of the Age was the re-birth of Israel?
There are several reasons. First, the Abomination of Desolation can’t happen til there’s a Temple, and there can’t be a Temple until there’s a covenant keeping nation in the Promised Land. In Ezekiel 36:24 & 37:21 God promised that Israel would be gathered together in the Land sometime before Israel’s Kingdom Age begins. The dry bones prophecy in Ezekiel 37:1-14 hints that they would first be gathered in unbelief and then God would put His Spirit in them and they would know it was He who did this. I think Ezekiel 39:22 tells us this realization will begin to take place after the Battle of Ezekiel 38.
Isaiah 11:11 and Amos 9:14-15 agree there would be an end times regathering. This happened in 1948 and was the first clear sign that the End of the Age was upon us.
In Matt. 24:15-21 Jesus said the Abomination of Desolation would be the sign that kicks off the Great Tribulation, a time that is specifically defined in Scripture as being the last 3-1/2 years before Daniel’s 70th Week ends, followed shortly by His return. To me it doesn’t make sense that the Lord would say that all the things He had spoken of in Matt. 24 will happen within one’s generations lifetime, as He did in Matt. 24:34, after giving a start time that’s clearly only 3-1/2 years from the end. Therefore, since none of them could have happened before there was a nation, I believe all the events of Matt. 24 begin with the re-birth of Israel.