How could Princess Leia remember her "real mother" a "little bit," when Padmé Amidala died in childbirth?

I've always worked on the assumption that Leia didn't know she wasn't an Organa for real. She never knew she had a "real" mother because Breha was her mother. Breha also died while Leia was between 12-16. This is roughly 10-15 years before "New Hope"(my guess). Things happen, and that could be why her memories of her mother are fading.

There is, however, no evidence that she knew or didn't know she was adopted. The only thing we have to go on is Luke's choice of words:

LUKE: Do you remember your mother? Your real mother?

This COULD lead us to believe that not only did Leia know, but others knew as well. If you go off that, then the only explanation of how she remembered Padme is with the help of the Force.