The Eternity Code question

I am currently reading the third Artemis Fowl book, The Eternity Code. In this book Juliet is supposed to replace Butler and be Artemis' temporary bodyguard. I find this really interesting because in some ways Juliet is like her brother. Whereas in other ways, she is totally different. For example, compared to Butler, Juliet has more of a teen like perspective on things. She is not as serious as Butler when dealing with problems. Although she does try to act like Butler at times. Also, sometimes she makes many decisions without thinking of the proper consequences.