Validation for 2nd monday from today

I am new to SharePoint and I'm trying to do a validation for greater than or equal to the 2nd Monday from today.

I'm creating a work request form and I want to make sure they can't make a due date sooner than the 2nd Monday. So If a request is put in the week of 1/11 the soonest turnaround is 1/29. Also, I would like to make that the default value.

How would I achieve this?