Where can you make a three-point turn while driving?

I was taking my driving test, and my examiner ask me to make a turn around or U-turn. I was about to perform a three-point turn, first by entering the center of the left turn lane to go back to the opposite direction. But my examiner stopped me while I was about to put the car in reverse, signal, but my examiner stopped me midway, asking me to turn anyways to the opposite direction. This was in the middle of the road, where I had to wait until there were less cars before I can do the three point turn. Was I doing something wrong? Or it because I was to slow when I did the three point turn? Or was it because the street was not exactly narrow, so you don't necessarily have to do a three point turn, but just do a normal u-turn? Can someone explain this to me, I will be retaking my driving test very soon!