Looking to Select a date and have all Cells 90 days before that date turn red

Hello,

I am working on a spreadsheet where my Co-Worker would like to enter in a date such as 3/22/19 and have all the dates that are 90 days prior to that date or greater Turn red. I know i can just do a conditional format for this but i am trying to have it so she can change the date on the fly.

I have attached a sample spreadsheet.

I would Like Cell A1 be where the date is to be entered and then Columns 2, 3 and 4 be the dates that would be searched through to find dates that are 90+ days prior to the date entered in Cell A1.

Thank you for all your help.