The timeline confusion that persists among modern viewers largely traces back to Candace Bushnell's prequel novel The Carrie Diaries and its subsequent 2013 television adaptation on The CW.
In HBO's flagship series, Carrie repeatedly states that she lost her virginity in eleventh grade behind a local recreation center to a boy named Seth Bateman. Her arrival in New York City during the late 1980s was characterized as gritty, financially precarious, and sexually active, matching her 1988 pregnancy revelation.
The CW series, however, smoothed over Carrie's teenage years. Designed for a younger broadcast demographic, the prequel altered the timing of her move to Manhattan, introduced a protective suburban father, and delayed major sexual milestones. Because The CW operated outside HBO's creative control, casual viewers who watched the prequel assumed the original show's timelines were nullified. For fans of original series continuity, however, executive producer Michael Patrick King maintained that the HBO run, including Carrie's 1988 medical history, remains the definitive canon.