No worries my young friend. I did not went for the IPPT test prior to enlistment and they threw me into the PTP batch (extra two months). But I think on the second or third week of the training you will get to clear an IPPT test. Those who pass can get to disrupt from the two months training and await the actual BMT training.
I think after the first test there will be subsequent tests for you to try and pass. And you can still get to go home after you pass but obviously you dun get to spend as much time as the first batch of disruptees. I dunno if this is still the same now. But do try hard to do your best during training, you will be surprised how much you can improve within a short one or two weeks.
I was the first batch of disruptees in my Company, there were only 30 plus disruptees for the first batch. It was quite a proud moment as the passing rate was low and the sergeants asked us to write messages of encouragements to fellow trainees. They had the messages pasted on the notice board of the company line. And damn, I was really happy to go home and relax for more than a month before the actual BMT.
I really ran my hearts out for the 2.4km (I am quite a big guy, so that was my biggest problem). I remembered passing out at the finishing line, and had the medic attending to me, it did not help that I was running a fever prior to the test. I came in 12.04 seconds btw. Not great, but enough.
Those were the days. Have fun man.