As it was turf that you had laid, you should be able to cut it when you can no longer take hold of the edge of a piece of turf and lift it. Once it has begun to take root, you shouldn't have any problems. Let the grass dry out, and keep the mower on a high setting for the first few cuts, then gradually reduce the cutting height so that the grass is cut to your desired length. It is also worth changing your cutting direction each time that you cut the lawn.
