For those looking for a non-VBA method. I have used this method successfully.

1- Insert a new date picker content control from the Developer Tab.
2- Select the Design Mode in the Developer Tab.
3- Delete the "Click here to enter a date." default text.
4- From the Insert tab, select Insert Date and Time.
5- Select the style of the default today's date style and check the Update automatically box.
6- Right click the date picker content control and select properties.
7- Select the matching date style for the date picker.
8- Turn off the Design Mode in the Developer Tab.

Will display today's date by default instead of the content control's creation date.