Sorry, mama... But...
Maybe there was another reason why your mom recommended it, and you just haven't gotten to that part yet?
I mean... (and I'm guessing, here), you said that she recommended it to someone who she knows would be affected by it. Does this mean that you suffered a similar trauma in your life? Maybe the book isn't just about the incident that you just read. But maybe the important part, (the reason your mom wanted you to read it) comes after that -- the healing part?
Ask your mom why she did it. Maybe that's the reason, and if so, maybe you can find the strength to pick it up and finish it, because... oh, I don't know. Maybe mom is right?
Sorry... Just playing the devils advocate for a minute. Sometimes mothers, even though we don't always understand their methods, really do know what's best for us.