I followed the schoolbus on Hebe's first day and cried all the way for no apparent reason -and she'd already been to preschool for 4 years....
it might not all be fine, initially, but it will get there, eventually, and sooner rather than later, I suspect, with all the careful planning and thought you've given it. There's no point telling you not to panic or be terrified, but there's every point in reminding you how awesome you are in the parenting field.