You can schedule it whenever you like based upon your schools schedule. It all depends on how much time your school gives off and how long you want to study for it. Most of the schools that I have interviewed at give about 5-6 weeks off between second and third year so most students will take between 3-5 weeks to study and then take the test. Many will take the test a week before 3rd year starts in order to give themselves a mini 1 week vacation from school.