Reading oldest messages sent to your friend need too much scrolling if message history is very long. You need to keep on scrolling to get the first message and many times it becomes its very annoying. To make it easy and to jump to first message you ever sent to friend without scrolling, here is simple trick that you can follow. Refer these steps to Read Oldest or first message On Facebook without scrolling.(Also see How to Block Candy Crush Saga or Other Facebook Apps Request )
1. Open https://m.facebook.com/messages/ in browser. This is mobile version of Facebook .Now click on friends chat whose first message you want to view.
2. Once you have open chat history of your friend, Find for “See Older Messages”. Right click on it and select Open in new window.
3. In new window opened you will see a long URL in address bar .In this long URL you will find short piece of code saying like “&start=14”. The “14” or any other number refers to the indexed messages that appear in your conversation .Your messages are indexed from 1, 2, 3 … from most recent to least recent. Now you need to set this value close to the total no of messages you have sent to your friend. But the problem is how you will know how many message you have been sent to friend to till now. To get this value Go to next step.
4. Go to https://www.facebook.com/messages .Next Open your friend chats you were viewing in above steps.
5. Now scroll up in the chat history that you opened in step 4 and have a look on the top of the chat history number. This number refers to total number of messages remained to scroll, in your message history. To get this this number you have to view it faster as it will disappear soon depends on your internet connection speed.
6. Now swap this number with number in step 3 and open long URL in which you swapped number i.e. URL of mobile version of Facebook. Only with few clicks you will able to read oldest or first message on Facebook without scrolling.
(Also see How to Delete Facebook Search History? )