Simplify the following text for a Grade 5 native English-speaking person.
Original: When she was caught taking a book before her mother read it , Olga would jokingly tell her mother that Alexandra must wait to read the novel until Olga had determined whether it was an appropriate book for her to read .
Simplified: Olga also liked choosing books from what her mother read . When she was found reading a book before her mother had read it , Olga joked that her mother must wait until Olga had made sure that it was a proper book for her to read .