Could you please tell me the precise meaning of "set us all back" in the following excerpt from the chapter five of The Great Gatsby?
“We haven’t met for many years,” said Daisy, her voice as matter-of-fact as it could ever be.
“Five years next November.”
The automatic quality of Gatsby’s answer set us all back at least another minute. I had them both on their feet with the desperate suggestion that they help me make tea in the kitchen when the demoniac Finn brought it in on a tray.
At this point in the narrative, the afternoon tea between Nick, Daisy, and Gatsby has started. Nick and Daisy freely greet one another and talk with an noted effortlessness. This is not the same for Gatsby. He has stressed about the floral arrangements, ensured Nick's lawn that was once raggedy is now cut neat and prim, and struggled to find the right pose to strike once Daisy was to see him for the first time. Gatsby feels that the enormity of the moment is not being received well. Essentially, Gatsby's worst fears not only lie in anticipation but they lie in expectation.
This condition of enormity is something that Gatsby carries with him. Daisy and Nick do not. They fail to recognize what Gatsby has understood leading to this moment. This particular instant is the embodiment of his life's work. From the moment he saw Daisy in Alabama, Gatsby made attaining her his life's work. Such endeavor is amost realized at this moment. Rather than be invigorated with the closeness and intimacy with which he can see and experience his dream, Gatsby is terrified by it. He feels it is "all wrong." It is impossible for Gatsby to "play it cool" with so much invested in this moment.
All of this is unknown to Nick and Daisy. They talk without hesitation and banter without reticence. It is this collision of realities- Gatsby's condition of stress and expectation with the lightness of Nick and Daisy- that his comment "set us all back." The idea of "set us all back" is to reflect a momentary hiccup in the ebb and flow of a discussion. When something "sets someone back," it is jarring, or out of context. It is unforesen and an anamoly to the situation. Gatsby's comment of remembering half a decade to the month when he and Daisy first met "set us all back" because it is an expression of weight and gravity in a condition of lightness. Gatsby's comment "set us all back" because it integrates reality in a situation that seemed to operate outside of it. For Fitzgerald, this becomes one of the most challenging elements of conveying the truth of real experience. It "sets" everyone "back" because it expresses honesty in a world that might not necessarily validate it. In this light, Gatsby's comment which is rooted in the real and authentic, "set us all back," it only for "at least a minute."