As a side note, you must be 21 in Florida to get a concealed carry permit. That would easily knock out at least 75% of the students (probably more since there are many more first, second and third year students students due to attrition). And as has been noted most are just trying to survive on what little disposable money they have and probably would not purchase a gun and go through the training. Concealed carry has quite a few monetary requirements in addition to the cost of the gun itself. In NC you can easily spend almost 200 to get a permit for the first time. I could see it being monetarily restrictive as to who could actually get the permits. And as red noted there are other more pressing wants for kids at that age.
Smarter than the average bear