Newly planted grass is very delicate and easily damaged versus established grass in a mature lawn. Care will need to be taken when mowing a newly planted lawn. Remember the ground is softer from the more frequent watering and the newly planted grass roots are still very shallow. Additional care should be taken to avoid creating damaged areas caused by turning your lawn mower too sharply over newly planted grass.
Turning too sharply causes the wheels of the mower to pull the grass and will uproot newly planted grass. It is a good idea to turn your mower over hard surfaces when cutting, like a driveway or sidewalk. If you do not have good hard surfaces to turn your mower then make several passes around the perimeter of your lawn and then use these larger areas to turn your mower as you cut your lawn from side to side.