Final answer:
The sentence that would most effectively move the plot forward is: "The excitement of my new job started to wane, and I began to reconsider if this was truly how I wanted to spend my summer."
Step-by-step explanation:
After sentence 6, the sentence that would most effectively move the plot forward is:
The excitement of my new job started to wane, and I began to reconsider if this was truly how I wanted to spend my summer.
This sentence would add a moment of reflection and doubt to the narrative, introducing a potential conflict for the protagonist. It sets the stage for further development and shows the character's thoughts and emotions in relation to their new job.
Learn more about Plot development in a personal narrative