Hilary Duff was about 27–28 years old during the first season of Younger , where she played 26‑year‑old Kelsey Peters.

How the age lines up

  • Hilary Duff was born on September 28, 1987.
  • Younger premiered in March 2015, and principal filming for Season 1 took place in 2014.
  • That means she was 26–27 while filming Season 1 and 27 when the show first aired, slightly older than her 26‑year‑old character.

Fun context for fans

  • One running joke in fan forums is that Duff looked believable as mid‑20s, even though she was closer to her late 20s at the time.
  • The show’s whole premise plays with perceptions of age in media and the workplace, which is part of why viewers still discuss “how old was Hilary Duff in Younger ” years after the premiere.

Many fans now revisit Younger on streaming and compare her “late‑20s playing mid‑20s” to how other actors play younger characters in today’s trending shows.

TL;DR: She was in her late 20s (about 27–28) while playing a 26‑year‑old in Younger.

Information gathered from public forums or data available on the internet and portrayed here.