Mine did it on the 3rd or 4th day after birth, at the private hospital. I think it's better do it earlier than later coz the wound is small tends to recover more quickly (he came out from the operation room after 20 min and he didn't seem to feel annoyed about the small wound thereafter)
By the time you realize that he really needs to perform it due to medical reasons (maybe by the age of 6 or so) it'll be a real pain for him to go through this operation. And it takes like a few weeks for the wound to fully recover...
Of course, check with your doc first to see if it's really necessary.