Age of Imam Mahdi (A.S.) at the time of appearance:

But from the point of view of Shiism:

The savior of the end of time is the son of Imam Hasan Asgari (a.s.) and is connected to the Prophet of Islam by a chain of regents, and all of them are innocent of sins and have received all divine knowledge through the intermediary of the Prophet of Islam. All the imams, including Imam Mahdi (A.S.), have knowledge of Ladni. And according to the narrations, his judgment, like the prophet David, originates from his inner knowledge and does not need an external witness. Having the Tablet of Hazrat Fatimah (PBUH), he is aware of everything before it happens. ) collected. He is aware of all the secrets of the Qur’an.

Imam Mahdi (A.S.) has been living his blessed life for thousands of years, so he has gained as much experience as the entire human race in this millennium. He has come closer to God through night vigil and daily fasting than all the prophets, messengers and guardians of God. With such a strong resume, he deserves to be the first and last person to rule over all the people on the planet.

  It is more important than the government to create justice, which has been one of the long-standing aspirations of mankind on a much smaller scale. In his government, even beasts do not harm other creatures.

 Sincerely, the Shiite opinion about the savior is closer to the truth from the point of view of reason and narration.