How to sort my tickets such that the oldest tickets are on the top of the tickets queue?

You have a good volume of tickets to handle on a daily basis and according to you, the tickets that have been sitting in the queue for a greater period of time would need your immediate attention. In this case, please explore the option of sorting in the tickets list view where the option that needs to be chosen is "date created" and in order to have the oldest tickets on top - please choose "ascending" along with this in the dropdown. 

Please note that this has many other options such as last modified, status, priority and due by date. Within that, you could choose ascending or descending.