Someone once asked...

why do they say today years old again

Someone answered with kindness...

It's a meme. It often refers to: "I was X years old" when I learned about this, e.g: "I was nine years old when the Nintendo 64 came out!" Or, "I was 50 years old when I discovered that Link was wearing a traditional Norse hat!"

Another soul answered...

It's fun to walk down the garden path sentence from time to time. A phatic conspiracy to enlighten the mood.