In Taylor Swift's “august,” James is 17 years old.
The song presents a brief summer romance involving a female narrator and James, who is already connected to Betty. The age detail places the story in an adolescent setting and helps connect “august” to the other Folklore songs that make up the same narrative arc.
“august” is told from the perspective of the girl who hopes the relationship might become permanent. Instead, the summer ends, James returns to Betty, and the narrator is left recognizing that the relationship was never truly hers to keep.
The characters and events belong to Folklore's fictional storytelling framework. Although fans have proposed autobiographical interpretations, Swift presented the album as a collection of imagined narratives and character studies. James's age is therefore a detail about the song's story, not a biographical fact about a real person.