Writing is quite possibly the best outward appearance of expression. For me, I am an introvert person, so I find that the anonymousness of posting online to be invigorating, and I post as an outlet, so to speak. I really don't want to discourage you, but writing a full-fledge novel is a huge task, or an autobiography in your case. Most publisher's won't even bother to read the entire thing at first, and if you don't follow their asinine rules (like formatting; indenting, 12 pitch, a certain font, etc) they'll just throw it away or send it back, no matter how articulate you are. You could be the next Stephen King, but if you don't come up with the allotted amount of words (in most cases 80-100,000), a publisher won't even bother to get beyond the title page. But I really don't have any experience with publisher's that publish autobiographies, it may be totally different.
Due to my current regime, it is extremely difficult to post online, let alone sit down for months and compose a 100,000 word book. But if it's something you're willing to try, I say go for it.