Good luck for man for your upcoming enlistment! Make these final
3 months of freedom count! And yup, its good that you're
maintaining your fitness; just watch your diet, if possible jog
three times a week (in NS they make you run everyday); go and swim
on other non-jogging days - it really helps alot in your overall
fitness. But don't have to chiong jogging or swimming now; just
normal moderate pace will do. As you get nearer enlistment, then
can start to increase the pace and load. 
Good luck once again!
