Well, I've noticed many people end up with a start date after a wake-up moment, like waking up after having blacked out, realized you got home, with the kids, and don't remember driving...that kind of thing. I woke up Saturday morning and realized I hadn't made dinner for the kids and saw the empty wine bottle on the kitchen counter and my hidden stash of a half-full whiskey bottle was empty. Somehow I managed not to get arrested or kill anyone by 7-12-14 and that became my start date. No point really in waiting, Mr. Liver wants a break! But sure, Thursday is better than never.
Whatever you do, try not to drink like a maniac the day before, try to cut back now so you don't have a bad withdrawal.