Not that it makes it any better (actually makes it worse) but Portman was 18 in TPM and Lloyd was 10 (well probably 17 and 9 during filming)

but the character of Anakin was supposed to be like 12 and Padme was supposed to be like 14 i think (maybe 16)

either way, it was bad, as while Natalie did look younger (Lloyd didnt look older) it wasnt young enough to make them look close in age. I think a lot of that had to do with maturity of the character (and the actual actor)

I agree that they should have used the same actor for all three or had a different actor for Padme in TPM

-Darth Simon