I would recommend "Jane Austen: A Family Record" by Deidre Le Faye. I've read about a half dozen biographies and she is considered one of Austen's best biographers.

She's the one that updated "Jane Austen's Letters" and is considered quite an Austen authority. Both of her books are widely quoted. Her biography follows a typical format, i.e., strict chronology.

The early part of her book that gives JA's genealogy I found boring and just skipped it.