There are a number of options. easiest is probaly just putting the date text box on page one but hide it, then it will always get populated, there is no reason for the user to see todays date every time they record something is there?
Or when the form loads just activate page3 then activate page1.
OnLoad event:
layer.Forms("EDITFORM").pages("Page3").activate
layer.Forms("EDITFORM").pages("Page1").activate
This is untested.
OR write the date directly to the file on the featureadded event. this requires is a little bit more code