We bought this wagon for our daughter's first summer (she is 8 mos).  It is perfect!  Even though she is small, she sits perfectly on the seat and the seat belt holds her in place!  It moves very well, sometimes one of the wheels seems to get stuck sideways but it doesn't impede the way the wagon moves.  We've used in on grass and on the sidewalk and haven't had any problems.  Baby girl loves her first wagon!