Your absolutely right because from memory he wasn't born until about fifty years after Jesus and would have been middle aged by the time he finished his "Antiquities" if not older.
The text is different in the Hebrew and Roman versions of his work which means one or the other has been tampered with.
First, it should be noted that Josephus was not writing dead history from the vantage point of some imperial library; he was writing of the events of his day.
He was an eyewitness of most of the events he chronicled.
His account is the more fascinating because he served actively during the Jewish-Roman war on both sides, beginning as a general of the Jewish forces in Galilee, and ending as an adviser to General Titus.
So close did his friendship with Titus and his father Vespasian become that Josephus later adopted their family name, Flavius, which is why he is known to us as Flavius Josephus, and not by his Jewish name, Joseph ben Matthias.
Born a few years after Jesus' death, in 37AD as he grew older Josephus became a keen observer of political trends.
He was of noble birth, a member of the religious sect of the Pharisees and had family connections with the more aristocratic sect of the Sadducees.
He tells us that at the age of 26 he was sent to Rome as part of a group to secure the release of certain Jewish priests, who had been sent in bonds to Caesar by the Roman procurator Felix on "small and trifling" charges.
This instance recalls to readers of the Bible the difficulty that the apostle Paul had with this same Felix, who kept him imprisoned for two years, hoping for a bribe. (Acts 24:27)
While in Rome, young Josephus formed a friendship with none other than the wife of Emperor Nero, the Empress Poppea, who intervened to free his friends.
When Josephus returned to Jerusalem, full of admiration for Roman culture and military power, he was aghast to find the Jewish nation more and more bent on war with the Romans.
It was during this period that Josephus was able to see with his own eyes the events that proved the truth of Jesus' notable prophecy against Jerusalem.
Jesus had foretold "great necessity upon the land and wrath on this people," and Josephus made note of the wrath of the Romans, who had originally been inclined to be lenient with the Jews, but had been infuriated by the unwillingness of the Jews to yield.-Luke 21:23.
When the city fell after a relatively short siege of four and a half months, the Roman soldiers killed until they were too tired to kill any more. "They slew those whom they overtook without mercy, and set fire to the houses whither the Jews had fled, and burnt every soul in them, and laid waste a great many of the rest; and when they were come to the houses to plunder them, they found in them entire families of dead men, and the upper rooms full of dead corpses, that is, of such as died by the famine .*.*. they ran everyone through whom they met with, and obstructed the very lanes with their dead bodies, and made the whole city run down with blood."
It is of interest to note that not only the ferocity, but the very brevity of the siege of Jerusalem had been predicted by Jesus when he said: "In fact, unless those days were cut short, no flesh would be saved." (Matt. 24:22)
During the siege, Josephus watched in numbing horror as the Jews pitched 600,000 bodies over the walls of the city, victims of the famine, disease and factional warfare in the city. At that rate, everyone in Jerusalem would have died in another five months!
Josephus tells us that the total of Jewish dead in the siege reached 1,100,000, and defends this figure by pointing out that the siege occurred when great multitudes of pilgrims were in Jerusalem for the Passover festival. Josephus' figure has been doubted since the Roman historian Tacitus gives a lower figure-600,000.
However, it should be remembered that Tacitus was not an eyewitness.
His writings are full of inaccuracies regarding Jewish history and customs, and he admits that his casualty statistics were received secondhand.
Josephus further defends his figure of 1,100,000 by pointing out that not long before the Roman invasion of Judea a count had been taken of the number of animals sacrificed during the Passover and it was found that 256,500 had been killed.
Since an average of 10 persons would eat the Passover meal from the same animal, Josephus concluded that as many as 2,500,000 persons could be found in Jerusalem for the Passover.
Josephus' credentials as an eyewitness historian are impressive.
Of course, he was not an eyewitness to events inside the city of Jerusalem during its siege, but he was able to procure the freedom of some 200 Jewish survivors after the fall of the city and he could have interviewed them.
During the siege there was also a steady stream of Jewish deserters, and Josephus was free to interview these as well. Additionally, he apparently had access to the diaries and commentaries of his patrons Vespasian and Titus, since he refers to these documents in his later writings.
But there is no reason to doubt the overall accuracy of Josephus' work. After all, it was written during the lifetime of all those involved in the events being chronicled.
Any serious inaccuracies would have been pounced upon by the author's many jealous detractors.