Think about it: you’ve already written much about your life story. Before about ten years ago, we called these write-ups “letters???; we wrote them on paper and mailed them to friends. Today, of course, we do that through email and blogs, and we may forego capitalization and proper spelling and grammar—but we do still share our emotions and recount our activities for all those interested in reading about us. So consider how much is already out there for you to capture.
The obvious advantage in getting hold of your own past writing is that you don’t have to write that part again! The other benefit is that your recollection of the described events will be fresher than it will be if you try to write about it now. Even if you don’t use what you’ve written word for word, your previous writings can serve as part of your research. Certainly if you were writing a biography of someone else, you’d be interested in attaining copies of that person’s original letters and emails.
Many people save letters and emails. It wouldn’t hurt to ask your friends and relatives to search through their attics and inboxes for stacks of your mail and “search results??? of your email. I’ll bet it will provide fascinating reading for you, and when you glean the important sections to include in your memoirs, it will prove just as fascinating for your readers.