I’m prior service and have no idea what to expect. How should I prepare for 91a school?

Just let the Instructors teach you the MOS. You will be in barracks with other reclass Soldiers. Should be able to have your car and not be bothered for the weekends unless you guys do something stupid. Unless you in class with them stay away from all the Initial entry Soldiers. Just like they all have COVID and you don’t want what they got. Fast way to get kicked out is to mess with one.

Have not been through the schoolhouse but as prior service reclassing to 91a yes you will be with new recruits. The class will be mixed unless there is enough prior service to form a class by itself. However while you may be classed with them, that is about as far as it goes. You will be treated different than raw recruits. More privileges, civilian clothes, etc. As long as you do not give the DI's flack they will treat you with respect.