MuMu was only 14 when he joined the Sky Army, he became a leader at the age 15

Lox was 10, he was a founder so he became a leader instantly.

Benja joined when he was 10, but didn't become a leader until he was 16.

Fluffy was 13, he became leader at age 15.

Sky was high leader at the age 11. He's 20 now

Brotato joined when he was 16, he only got to Gaurd of Leader when he was 17.

Sundee was 14, he became a leader at the age 17.