Wow, you guys are late to the party. You didn't set your alarms did you?
https://forums.macrumors.com/showthread.php?p=20965484#post20965484
The email confirmation for my Space Black Stainless Steel pre-order came through at 8:24am BST (12:24am PDT), with a non-specific "June" delivery date. Less than half an hour after pre-orders went live.
Even if I'd got it though twenty minutes earlier, I'd be looking at mid to late May for delivery, given that the Space Black version was one of the various ones that simply was not available for the earlier 24 April - 8 May delivery window, no matter how early people pre-ordered it.