Oh yea, my mistake. I thought normal is 24 months, PTP is 26 months, haha. So, should I save up all my leave and use them all on my last few days(how many leaves do I get?) or should I just disrupt my NS and serve after I graduate.
By right you're not supposed to do that but you can speak to your OC then to see the kind of arrangements he can make for you. For now, just focus on getting your placing first, then talk about deferment. None of us here can give you a concrete answer because it really depends on where you're posted to.
Edit: Anyway, if you don't get your placing next year, then deferment in 2018 might be a bit tricky because deferment administration cutoff period is around April, which will cut it a little too close. In SAF, it doesn't mean you say you want defer then next day can defer already. Your OC will need to notify the S1 and start your own deferment processing. All these administration will take time. Even if your OC wants to let you defer, it will also be subjected to approval.
My advice is that be a good solider while serving so that your OC will be more inclined to help you. It's not his job to handle all these for you but rather out of goodwill. Must remember that deferment is always a privilege and not exactly a right, so don't make things difficult for any parties.