Josiah was just eight years old when he became King. Eight.years.old. I don't know about you, but I don't know many eight year olds with the character to handle the title of King. It seems Josiah was determined to do this thing right. He did right in the sight of the Lord and in the eighth year of his reign (at age 16), the Bible says he began to seek God and by the twelfth year (20 years old), he began to purge Judah and Jerusalem of the high places, the Asherim, the carved and molten images. He tore down the altars of Baal.
Risky. Israel had been deep into worshipping pretty much everything but God. Here comes this new King, a young lad, who tore all of it down.
Josiah made a choice. He could have continued building altars to other gods as the two young Kings before him did. Instead, he brought about change, good change.
2 Chronicles 35:24 says that when Josiah died in battle, that Judah and Jerusalem mourned for him, the same Judah and Jerusalem who Josiah came in and tore down their idols. I would say that was a change that was good and right and executed well, so well that the Bible says throughout his lifetime, they did not turn from following God.
Change can be risky, but when a leader walks humbly and obeys God, it brings lasting change, no matter how young you might be.
"Let no one look down on your youthfulness, but rather in speech, conduct, love, faith, and purity, show yourself an example of those who believe." 1 Timothy 4:12
Scripture reference: 2 Chronicles 34, 35; 2 Kings 22, 23