The 'I Was Today Years Old' meme is a popular social media phrase used to express the moment someone discovers a common fact or a clever life hack far later in life than expected. While its exact origin is difficult to pin down, it became a viral sensation on Twitter and TikTok in the late 2010s, often accompanying videos of hidden product features or surprising etymologies. It serves as a humorous way to admit one's own ignorance while simultaneously educating others. The template is widely used across all platforms to highlight 'mind-blowing' information that was hiding in plain sight, making it a staple of internet culture for trivia and educational humor.