Why in the world would they allow you to pick it up BEFORE delivery? If that were the case, then there would be a line around the block at the delivery centers at 8 am, and if you supposedly work, how do you have the time to get it at 8 am and not interfere with work, but not be home for its delivery during the day? If you want to pick it up you can on the day they attempt delivery. It sounds like you're just whining to try and get it earlier. IF you're at work all day, you can wait and pick it up after work. Since the delivery date is the 21, you're lucky they'll even let you pick it up without waiting till the next day (since technically delivery can take place anytime on the 21st.
Just calm down, call tomorrow morning and tell them you want to pick it up after work, and by 6 or 7 it'll probably be ready.
Remember, if you CHOSE to have it shipped (mind you they charged NOTHING to ship it from CHINA to your door 10,000 miles away), that was your choice. You're more than welcome to go stand in line at a store and try your luck, or have done in-store pick up and picked it up any time convenient for you.
So tired of seeing people complain about Apple when it was their own choice to order the way they did.