Two simple approaches. One is to add an extra column with serial numbers and then sort on that column in descending order. This works for small amount of data. For large data it is best to import it in Power Query and choose Transform tab – Reverse Rows.
Benefit of Power Query? It works on a smaller sample of data and then applies the transformation when you choose Save and Load option. This is much faster than getting all the data and then trying to sort it (which is the first method).
Why is this required? Usually required with logs where the first transactions or rows are at the bottom. So the data is received in reverse chronological order. Twitter feeds, Timeline Updates, Live blogs – all follow this pattern.
This method works independent of the time-stamp column. What is wrong with timestamp? It may be in different time formats, some rows may have same timestamp and some rows may have no timestamp at all.