Got May 1st but it is a later time than I had hoped. Hoping that I can catch someone's cancellation!
The same thing for me on my initial try but then another poster told me if you hit refresh on your browser when it shows you the two time options, it will give you a different window. I just went back and changed mine, had to hit refresh about 15 times but finally got my perfect window. It doesn't change your current ressie until you hit confirm so if you can't find it, just cancel the changes.