You don't have to add a header to every Excel worksheet individually when you can group them first.

Have you ever tried to drag the header columns in an Excel spreadsheet to make them fit the text? I have and just when I think I’ve got it right, a quick glimpse down the line of columns usually ...

You can sort data by dates in Microsoft Excel and Excel Online. Learn how to sort all the columns according to date column using this tutorial.

Now, you can sort the copied list by clicking any cell in it and choosing Sort from the Data menu. By default, Excel selects the Header Row option. Be sure to update this option accordingly.