I would bet the employee told you it comes in on Thursday because they do not know how Product Process works. Usually the person who answers the phone is just a customer service type person. I bet your store's regular trucks come in on Thursdays, but the game will be delivered in a drop shipment, just like almost all other media (games, music, movies...).
It should be there tomorrow. All of the recent games, PC and console, have released exactly when they were supposed to...Civ 5, Starcraft, all the Sims crap...all have been in store at open on release day in the last few weeks, and I expect our game to be the same. If you pre-ordered it, it should be there.
Go out tonight with your buddies/girlfriend/boyfriend/husband/wife and give them these last 12 hours before release since you probably won't acknowledge their existence for the next week. Have some fun. It will all be good tomorrow.