If they are all in dmy order, then I'd go into windows control panel and make
sure my short date is set to this same dmy order.
Then just change all the . to /
and change all the / to /
And then I would give that range an unambiguous date format (mmmm dd, yyyy) and
check if my dates are what I expect them to be. Your results could be
dates--just not what they really should be.
Then sort your data.
And after you've verified them, you can change the windows short date back to
the order you like.
Are you saying that this is what you would like to have happen, but it
doesn't happen now? I suspect that all your "dates" are really text
values, as a full-stop is not normally used to delimit dates. Convert
them to real dates as explained earlier, then you should be able to
sort.