Natalie Portman was 18. Her character, Princess Amidala, a fairly elected democratic leader of a planet that is apparently VERY HARD UP for good leadership, so much so that they elected a 13 year old to run the planet! Amidala was 13 in the first movie. Anakin is 6. Natalie Portman and Kieran Knightly actually switched places every other scene, so that it was never really clear to the people filming (or those watching closely) who was playing the queen at any given time.
When next they meet, Anakin is 16, and she's 23. So she's the one cradle-robbing, even though Anakin makes the first, second, and third move. Oh, and Padme has a bare midriff for the end of the movie, after the cat fight but before she falls out of the helicopter-thing.
In the last movie, I guess Anakin is 20-something, and Amidala is 30-something and heavy pregnant with twins.
Fifteen years later, father time has taken a bat to Obi-Wan, and Ewan's jedi knight is in his 60s. Not that time was any kinder to Anakin, who four years later is in his 50s/60s as well, despite being almost twenty years younger than Obi-Wan.
-kv