Baby from Good Luck Charlie has started 9th grade and people are saying they're 'officially old'

The actor who played the baby in Good Luck Charlie has just started 9th grade – yes, really – and fans of the show can't help but feel 'officially old'.

Mia Talerico starred as the titular Charlie Duncan in the popular Disney sitcom, which ran from 2010 to 2014 and spanned four seasons.

Set in Denver, Colorado, the show followed the Duncan family as they adjusted to the arrival of their fourth child, with the three eldest kids roped in to help raise their little sister.

Each episode was formatted in the style of a video diary, which second-eldest child Teddy (Bridgit Mendler) makes for her little sister in the hopes that her advice can help her as she grows older – with each entry ending with the message: "Good luck Charlie."