Book review 1-3 [The Princess and the Pea]

I read 'The Princess and the Pea'. This book is new one in our library. The story is easy and simple. A prince looked for a real princess. Many princesses went to meet the prince, but every princess was not a real princess. One day, a drippy princess came to the castle. The queen made her bed. There were too many mattresses. There was a small pea under the mattress. The princess noticed it so she became a real princess. Why the people who notice the pea are a real princess?? I don't know the answer but the story was interesting for me!