וַיִּקְח֞וּ כָּל־עַ֤ם יְהוּדָה֙ אֶת־עֻזִּיָּ֔הוּ וְה֕וּא בֶּן־שֵׁ֥שׁ עֶשְׂרֵ֖ה שָׁנָ֑ה וַיַּמְלִ֣יכוּ אֹת֔וֹ תַּ֖חַת אָבִ֥יו אֲמַצְיָֽהוּ׃
And all the people of Judah took Uzziah, who was sixteen years old, and made him king in the room of his father Amaziah.
Read halakhic rulings (Jewish law) on II Chronicles 26:1: and classical halakhic sources.