It has been noted that girls tend to be twice their height at 18 months of age when they reach adulthood. Share this: Print (Opens in new window) Print Share on Facebook (Opens in new window) Facebook Share on LinkedIn (Opens in new window) LinkedIn Share on Reddit (Opens in new window) Reddit Share on Tumblr (Opens in new window) Tumblr Share on Pinterest (Opens in new window) Pinterest Share on Telegram (Opens in new window) Telegram Share on WhatsApp (Opens in new window) WhatsApp Share on X (Opens in new window) X