I got the last of my application submitted the first week of January, so I think it was the second round. From something I read (I don't remember where), IHEID is releasing decisions between 1-15 March, so there is still time for everyone to hear back. As for my age, I am actually pretty young at only 21, so I was really excited to be admitted.
I applied for the MA in International Affairs (International Politics) and received a funding decision directly in the letter. The instructions for the financial aid were, however, on the second or third page of the letter. I would assume anyone who applied for aid would have to have the instructions for viewing the aid decision.