Do I have to tell my parents if I want to get tested?
That depends on where you go to be tested. Some clinics want your parents' permission before they offer you a test.
Most clinics are confidential. No one else will be told about your test results. You can call a clinic before going there to find out what its policy is on keeping your test confidential.
It's a good idea, though, to talk with an adult you trust about your concerns. A trusted adult can help you sort through your options. The adult can also help you think about your behavior and what to do about behavior that puts you at risk.