Judging from the age group we have 10 years would put most of the students at being on their own for 2-4 years after graduation. However that is a long time so it might be advantageous to say that they set out early because of the rising crime rate around the globe. It would mean that they still have things to learn but it would need to be on the fly. It would also make the loss of the academy a harder hit since it would still seem almost like home. Otherwise just about everyone will be in their late 20s. Not really a bad thing but I think that the bad guys wouldn't wait that long before taking advantage of the situation.