pregnancy test

Me and my boyfriend had sex on my most fertile day the 21st of this month 2 days ago . My next period should be starting on the 6th and it's usually about 5 days long . What day should I take a pregnancy test and get the most accurate results? I know a lot of tests claim to be able to get accurat results before my missed period but I feel like if I try taking one before the chances of accuracy aren't so good