Stewie is forever youthful, but his specific age is shrouded in secrecy. It's unknown the specific duration of time Stewie entered existing. The infant persona from
the animated television show "Family Guy" is forever young. His age is yet to be discovered.
Stewart Gilligan Griffin, the mischievous baby genius, is keeping his age a secret from the world. Speculation is rampant as to the length of time he has existed. Is he a century old? Or is he a newcomer? Only Stewie knows! This enchanting character continues to captivate fans with his hidden age and perpetually youthful visage.
Stewie Griffin Wikipedia