Help saving PDF form into true 5x7 invitation size

[jillf90255681]

Hi, I'm having issues saving my PDF form so it will be a true 5x7 invitation size. I am saving the file from Illustrator and importing it into Acrobat so it can be filled out by the customer.

However, when I save everything from Acrobat and test it by uploading to a printing website (such as vistaprint), I am not getting the invitation sized appropriately. I am sure this is user error. The invitation is cut off on the right and left and not tall enough. Any help/suggestions is greatly appreciated!

[try67]

What is Acrobat reporting as the page size? If it's only one page you can find it under File - Properties - Description.