Preventing Date of Less Than 3 Days Into the Future

Hi All:

Newbie here, and I'm trying to come up with a way to prevent a user from selecting a date that is less than 3 days into the future in a date field. For example: Today is March 23, 2015, and I'd want a user filling out my form today to have to select a date on or after March 26, 2015.

Thanks!