At the moment it could go either way.
However, with the timeline set my George Lucas, giving 20 years between Ep3 & ANH and only 2 years between AOTC & Ep3 it seems unlikely. Even if Anakin and Padmé concieved during AOTC then the children would only be 15 months old in Ep3 and that would be a maximum.
As OB1 indicates that Luke and Leia were seperated at birth, and we are 99% sure that Anakin does not turn in AOTC, it would seem reasonable to assume that the twins will probably be born at some point in Episode-III.
Thus, unless Episode-III takes place over at least 6 months or so it would have been hard for Leia to remember Padmé.
Therefore, I summise that Padmé and Leia go into hiding towards the latter half of Episode-III. 😉