It will not be accurate this early. From the time of ovulation until implantation is about 7 days. If you had intercourse around the time of ovulation then 6 days before your missed period would be accurate.
Do you mean this Wednesday, as in the day after tomorrow? I would wait. Two days is not much time to wait. Besides, if you only had sex last night and not earlier, and your period is due in two days, you probably aren't pregnant (wrong time for ovulation) so it would be a waste of a test.