Natalie Portman was 16–17 years old when she filmed Star Wars: Episode I – The Phantom Menace and about 17–18 when it was released in 1999.

She was born on June 9, 1981, so during the prequel trilogy:

  • The Phantom Menace (released 1999): filmed mainly in 1997; she was around 16.
  • Attack of the Clones (released 2002): filmed around 2000–2001; she was about 19–20.
  • Revenge of the Sith (released 2005): filmed around 2003–2004; she was about 22–23.

So if your main question is “how old was Natalie Portman in Star Wars?”, the simple answer most fans go with is: she was a teenager (about 16–17) when she first played Padmé Amidala in The Phantom Menace.

Information gathered from public forums or data available on the internet and portrayed here.