Why is scout pleased when jem fights her back why is she less pleased when he tells Atticus about dill?

As the novel progresses, Scout is worried about Jem growing up and separating himself from her. When Jem fights back, it is just like old times; Scout still feels that a little of her childhood is alive. It isn't until Jem reports to Atticus about Dill running away from his parents that Jem breaks the final code of childhood.Jem has reached a point of maturity where he can gauge situations and their seriousness. This is definitely a sign that Jem is becoming a young man and Scout doesn't like it.