Jesus said that it would happen it their generation, and they believed this. In the book of Revelation he told them these things would happen soon. Why is this so hard to accept????
In the Temple Discourse, Jesus warned the people hearing Him that Jerusalem would soon be razed and to flee the city when Armies began camping all around. This was fulfilled when the Roman armies encircled the city but delayed their attack while their commander went back to Rome to participate in the Caesar succession. Then, after he was appointed Caesar He and his son attacked.
Jesus foretold that not one stone would remain upon another of the Temple his disciple saw gleaming in the sun as they crossed from the Temple to the Mount of Olives.
Except Jesus didn't say EVERYTHING would happen in the generation of the people he was speaking to. He said the generation living at the time of certain events would not pass away until all the things came to pass (see Mark 13:30). So if you are correct and Jesus was talking about the first century A.D., then you will have to explain why ALL the things foretold in Revelation of the end times have not happened yet.