Board Thread:The Panopticon/@comment-7302713-20130331225051/@comment-1209840-20130401011432

The Goddess is correct. Amy didn't remember her family before The Big Bang, but after The Big Bang she suddenly does. The mini-episode Good Night discusses this phenomenon in detail.

AMY: My life doesn't make any sense... When I first met you I didn't have parents. I never had parents... and then you did whatever you did to reboot the universe and I had parents. And I've always had parents. And I remember both lives in my head at the same time.

THE DOCTOR: Everyone's memory is a mess. Life is a mess. Everyone's got memories of a holiday they couldn't have been on, or a party they never went to, or met someone for the first time and felt like they've known them all their lives. Time is being rewritten all around us every day. People think their memories are bad. Their memories are fine. The past is really like that.

AMY: That's ridiculous.

THE DOCTOR: Now you're starting to get it.

Anyway, Amy had no memories of the alternate universe in The Wedding of River Song until after that episode. Then, suddenly, she did have those memories. That's ridiculous. But that's what life in Doctor Who is really like.