If you are more liberal with your flag bridges you could do this to your hearts content and simply call TGs TFs...
But you hit a small issue with the ranks in Aurora...the lowest rank is Lt. Commander, that is generally speaking either a division head on a capital ship or else the first officer or commander of a smaller ship. That is the ground force equivelent to a captain. So a lot of what you are asking for is handled in the real world by Lts of various grades which aren't in Aurora anyway.
The academy is more "leadership school" or "staff officer training" then it is where fresh officers come out...that is Ensigns and the like. The age of the new officers is well younge...Lt. Commanders are likely closer to 31 years old then 21 years old. 21 is also very young for scientists and adminstrators...4+2+3=9+18=27 is minimium for Ph.Ds. and Admistrators are likely 18+4+1= 23 years old (MBAs).