NOTICE- Jesus is a fictional character. There is NO historical evidence that he ever existed for real.
The gospels sort of go with the age of 33 when he was crucified, but historically that is harder to verify.
Jesus was born some time between 6BCE* and 4BCE, during the reign of King Herod, as referenced in the gospels, and Herod died in 4BCE. The exact date of his birth is unknown, as Christmas is celebrated in lieu of earlier pre-christian holidays, to include the Roman Saturnalia a week long celebration introduced circa 217BCE to raise morale after a military defeat, usually celebrated as a week long festivity beginning on or about December 17 and ending on or about December 23. The other holiday was Sol Invictus, or the birth of the unconquered sun, celebrated on the 25th of December, setting the precedent for the season of Christmas and the whole 12 days predating Christmas as days of festivity.
Jesus's death is also murky on the exact date, other than the time frame of the year, precisely being during the time of Passover. Seeing as how all of the Disciple's of Jesus recognize Pontius Pilate as the prefect of Judea when Jesus was executed. The reign of Pilate as prefect dates between 26CE and 36CE.
So if my math is right he would be in the range of 30-42 years old at his time of death.
- I use the Common Era listing, as the Anno Domini calendar used by western civilization was created in the middle ages by Dionysius Exiguus, a Romanian monk, who created the calendar attempting to calculate the years since the birth of Jesus. Either he didn't have access to the correct historical documents, or Math was not his field or specialty, thus making the calendar inherently flawed.