My daughter, Charlotte ran to the tire swing but another girl got there first. So Charlotte silently backed up to wait. A few other girls showed up and started taking turns with the first swinger. Charlotte backed up further.

As grown-ups can attest, it's scary to speak up for yourself.
Can't we identify with Charlotte's feelings of insecurity as she wished the other girls would notice her and offer her a turn? The last thing she wanted to do was to speak up for herself.

People often stay quiet and get mad instead of being assertive. 
I watched an adult get overlooked at a fast food restaurant the other day. He didn't say a word to the (well meaning and busy) restaurant employees. He stood silent until he was so mad he shouted his complaints over the counter.