To answer this question you might find it helpful to compare Hannah at the beginning of the story with Hannah at the end, after she has had her experience of what the reality of concentration camps was all about. Note how the very first words of the novel are "I'm tired of remembering." We are presented with a Hannah who doesn't want to go and celebrate Passover and complains endlessly about being forced to go and remember what to her is a meaningless historical event that time prevents her from understanding. However, at the end of the novel, when she comes back and "decodes" the tattoo on her Aunt Rivka's arm, she truly learns the importance of remembering and why forgetting will never be an option again:
Hannah nodded and took her aunt's fingers from her lips. She said, in a voice much louder than she had intended, so loud that the entire table hushed at its sound, "I remember. Oh, I remember."
Hannah has learnt how the Holocaust still impacts on her today and why it is so important to go through the same rituals every year to remember the horrific loss of life. She understands more about her roots and heritage, and will never be the same again.
Hannah relized that the Holocoust is an impotant situation many people died and lost their lives, Hannah also relizes that all their jewish traditions are much more important. If you liked this book i suggest you read "Four Perfect Pebbles".