You have probably assumed that you would read your book in the order it appears in print, but remember that you don't have to. No one will be the wiser if you narrate the chapters in a different order.

First chapters often are packed with action or dialogue, and can make a lot of demands on your talent as an narrator. You want the beginning of your audiobook to draw your listener in. Plan to re-do the first chapter at least once after you have read some other chapters to see if you can't improve on your first efforts.

I recommend that you always try to record complete chapters during any recording session, rather than split a chapter between sessions. It is much easier for your listener to adjust to the inevitable voice changes between chapters than it is if your voice sounds different somewhere in the middle of a chapter.