Andrew Jackson first joined the Patriots in the Revolutionary war at the age of 13.
In between the conclusion of the Revolutionary War and the start of the War of 1812:
Jackson grew up
Apprenticed to be a lawyer
Moved to the new frontier of Tennessee
Served in the state constitutional convention as Tennessee got ready to become a state (1796)
Appointed as colonel in the Tennessee militia (1801)
Served in the Tennessee state House of Representatives and Senate