Okay but, consider that The First Order was still in the early stages of development when Armitage Hux would be attending Junior Academy and later the First Order Academy. His junior academy experience would have been one of the first trials for the First Order junior academy and was most likely on a star destroyer, in the wilderness of some remote planet, a tundra, or an underwater facility to avoid detection. Probably one of the two former options since the First Order had limited resources at the time. Whereas, they might have established an undwater academy ( much like the underwater weapons facility featured in Bloodline ) by the time Armitage graduated.
And honestly, Hux probably didn't feel the need for military combat experience after learning guerilla style warfare while surviving in the unknown regions with Grand Admiral Sloane & contributing toward the creation of The First Order. I wouldn't be surprised if Armitage went on supply runs as a child ( before his intiation into junior academy ) because he would be the least suspected, considering the New Republic was hunting Imperial war criminals such as Rae Sloane, Brendol Hux, and the other former Imperial officers they recruited during their travels. Organized military combat must have seemed so mundane after fighting to survive.
