This is written at about a first grade level, about a group of first graders. The story is simple, with a VERY obvious message about boys & girls both being able to play soccer well. The target audience (5-7 year olds) will definitely enjoy it, but older kids may be turned off by the moralizing tone and too-simple plot.
There's a problem on the playground! The boys won't let the girls play soccer with them during recess. Emma is furious! So she figures out a plan to get them to change their minds. And in the end they all learn the best teams are the ones that everyone gets to play on!