Tobirama Senju, the Second Hokage, founded the Konoha Academy. All prospective Ninja are to train here before they graduate.
Here are the Youngest known Academy Graduates from the Konoha Ninja Academy.
5. Itachi Uchiha
Itachi Uchiha was an Uchiha prodigy. He was also one of the brightest Uchiha. Itachi awakened a fully mature Sharingan at the age of 8. He also graduated from the Konoha Academy at the age of 7, making him one of the youngest ever Graduates.