Answer:
You really need to talk with your instructor. If you have been studying taekwondo for four years, you really ought to be ready to test for your black belt. Black belt tests are only given a couple of times a year. Your instructor can help you apply for your test. If your instructor does not think that you are ready to test yet, ask him or her what it is that he or she thinks you need to do to become ready, and then put forth every effort to what ever it is that they suggest. Being ready to take a black belt test is about more than skill level. You also have to display the proper attitude in class, and your behavior at home and at school must also be respectful and honorable.