I wasn't aware of this quote so I went looking:

Of course, the terrible things I heard from the Nuremberg Trials, about the six million Jews and the people from other races who were killed, were facts that shocked me deeply. But I wasn't able to see the connection with my own past. I was satisfied that I wasn't personally to blame and that I hadn't known about those things. I wasn't aware of the extent. But one day I went past the memorial plaque which had been put up for Sophie Scholl in Franz Josef Strasse, and I saw that she was born the same year as me, and she was executed the same year I started working for Hitler. And at that moment I actually sensed that it was no excuse to be young, and that it would have been possible to find things out.