What would you do if you discover that YOU are a Wizard and your parents don't Let you know a secret abut your family

There was once a Death-Eater, who was misunderstood as the evilest of them all, but she only bullied and hurt people to impress them! Then one day she had been chosen to be the Death-Eater leader, but must kill a child first to prove herself! What will happen will she kill the child? Or will she refuse?