The import screen suggested "Don't import" for the text before my first chapter. Why?

BookyAI looked at that text and recognized it as your original title page, copyright line, author name or a leftover "Table of Contents" heading — pages BookyAI regenerates itself in every export. Importing them would produce a duplicate title block and a second table of contents in the DOCX. The suggestion is only a default: if that text contains something you want to keep, change the selector to Preface (or any other destination) and it will be imported in full. If it mixes boilerplate with real prose, only the leading boilerplate lines are trimmed and the prose is offered as a Preface.