Just like the Active Duty Army, the Army Reserve is made up of Enlisted Soldiers and Commissioned Officers. You can make a huge impact by remaining as an Enlisted Soldier, but you may want to consider the Army Reserve an opportunity to achieve another of your military goals: that of becoming a Commissioned Officer.
Additionally, Soldiers with prior service may join the Active Guard Reserve (AGR). AGR Soldiers serve full time in units and organizations that directly support the Army Reserve.