I like the idea here - it does indeed meet the challenge - but I think you need to have more of the people in your shot and maybe not have a pole in the middle in the background.
No effort on any aesthetic part of photography, except the choice of subject. Poor lighting and no composition. Topic wise, a smart idea. What a shame.
Three photos in this challenge (Whoa, look out; Playground fun; Girls just want to have fun) were all taken the same day with the same camera, right? Snapshots are fun, but more care might be required for these challenges. I hope you and your friends had a good time anyway!
Next time try using manual focus or focus lock (if available) to get the girls in focus. It looks like the steps leading up to the flag pole are in focus more than anything else.