This verse did not begin a new chapter in the 1830 edition of the Book of Mormon. It was a logical break because it moved from Mormon’s personal interjection about his purposes in writing to the continuation of his story.
In context, this verse served that exact function. Mormon’s comments were technically out of place in his narrative, and therefore he needed to return to his planned history. He does it by recognizing that he had moved away from the text and needs to move back to the planned narrative.