Jehoiachin was 18 years old when he became king, and he ruled for three months in Jerusalem. He did what was evil in the LORD's eyes.
References for 2 Chronicles 36:9
In the springtime, King Nebuchadnezzar sent for him to be brought to Babylon, along with valuable equipment from the LORD's temple. Then he made Zedekiah his uncle the next king of Judah and Jerusalem.
Zedekiah was 21 years old when he became king, and he ruled for eleven years in Jerusalem.
References for 2 Chronicles 36:11
He did what was evil in the LORD his God's eyes and didn't submit before the prophet Jeremiah, who spoke for the LORD.
Moreover, he rebelled against King Nebuchadnezzar, despite the solemn pledge Nebuchadnezzar had forced him to swear in God's name. He became stubborn and refused to turn back to the LORD, Israel's God.
All the leaders of the priests and the people also grew increasingly unfaithful, following all the detestable practices of the nations. They polluted the LORD's temple that God had dedicated in Jerusalem.