When is the best time to take a home pregnancy test?

Today is May 26 and I am supposed to get my period on May 30. I have not taken birth control pills this past month. I have been experiences some symptoms that could be from pregnancy but also could be my period or wishful thinking on my part. Is it best to wait until I miss my period to test? I'm so anxious to know right now but I want to make sure the response is accurate. Is there a test that is pretty accurate 4 days before a missed period, or should I wait?