That command should work with one exception. You have mtime stating you want it to delete files that were created 24 hours ago and older. So if you just created the files they wouldn't be deleted.
And based on your description you said you wanted it to delete folders which where created 3 days before which I assume means 3 days and older. In that case you should be telling find -mtime +3
If you want to test it you can modify the mtimes using touch and tell it to use an older date.
touch -d '2007-01-31 8:46:26' some_file_or_folder