Stewie Griffin is forever youthful, but his exact age remains a mystery. It's unclear how old Stewie entered living. The toddler persona from the animated television show "Family Guy" is immortal. His number of years is yet to be determined.
Stewie, the clever little troublemaker, is impossible to determine from the world. Speculation abounds as to his actual age. Is
he over a hundred years old? Or is he a newcomer? The truth lies only
with Stewie! This enchanting character continues to intrigue fans with his unrevealed age and perpetually youthful visage.
Chris Griffin Wikipedia