Nintex form rule - date must be equal or greater than current date

I currently have 2 fields that ask for Estimated Resolution Date (date only) and Promised Follow-up date (date only) set in my list.

I tried this formula in the nintex form rule:

Is New Mode&&
lessThan({Self}, Current Date)

NOTE: Self = Estimated Resolution Date.

This did not work when i entered 7/1/2019 in the field during new mode/form preview. Any thoughts on how i can prevent users from entering a date before the day they are creating a new form for both fields?