AppleScript : repeat with each item from end to beginning

I’m trying to do a repeat form a list but I would to repeat from the last item of the list to the newest instead of the another way.

How can I do that knowing that this will do in the wrong order :

   repeat with each from 2 to count of items of creationDate         --     end repeat 

What I’m trying to do is to return the item number of the latest item which content the text “whatever”