Who joins Nick, Daisy, and Tom for dinner?

In the first chapter of The Great Gatsby, Jordan Baker joins Nick, Daisy and Tom for dinner. Jordan is Nick's love interest in the novel and also representative of the wealthy whom Nick condemns by the end of the novel. In his usual understated tone, Nick describes how he "enjoyed looking at" Jordan. He then describes her as "a slender, small-breasted girl, with an erect carriage" and "her gray sun-strained eyes looked back at me with polite reciprocal curiosity out of a wan, charming, discontented face." 

Nick's somewhat negative description of Jordan is punctuated with the way she speaks. She tells him (not asks him "if) he lives in West Egg "contemptuously." Nick then describes how she and Daisy talked "at once, unobtrusively and with a bantering inconsequence."

Finally, Jordan reveals herself to be a gossip. When the "fifth guest" of the party arrives—a phone call from Tom's lover, Myrtle—Nick explains that "Miss Baker leaned forward unashamed, trying to hear" and then she shushes Nick saying, "Don't talk. I want to hear what happens." She then explains Tom's woman in New York.

However, despite this negative characterization of Jordan, it's important to remember that Nick is telling the story from a year after the events of that summer took place. His storytelling is colored by his disappointed feelings of the  summer before and the sadness and anger he experiences after the death of his friend Gatsby.