How is Jem showing maturity in chapter 27 of to kill a mockingbird

They begin with a reference to the Radley Place, the source of childhood terror that no longer scares Jem and Scout-"Boo Radley was the least of our fears," Scout comments. The dissipation of Jem and Scout's youthful fear of Boo reflects how the trial has hardened them and how, in the wake of the trial's injustice and Bob Ewell's threats, the children have become increasingly mired in the more serious concerns of the adult world.