Jordan fills Nick in on the details of Daisy's life from the time she was eighteen until after her wedding to Tom Buchanan. Early on, Jordan had seen Daisy with Gatsby, then a young lieutenant, at Daisy's home in Louisville. At the time, Gatsby "looked at Daisy . . . in a way that every young girl wants to be looked at sometime."
The two girls stayed friends and Jordan was a bridesmaid at Daisy's wedding to Tom Buchanan. Unlike the poor Gatsby, Tom was an acceptable husband for Daisy's family because of his wealth--he gave Daisy a wedding gift of a $350,000 string of pearls.
Jordan, along with one of Daisy's family's servants, is the only person who finds out about Daisy's "cold feet" the night before she is to marry Tom. Daisy gets drunk for the first time ever, and will not let go of an important letter, presumably from Gatsby. Jordan helps Daisy overcome her panic and the wedding goes on as usual.