In the Sunday Washington Post Outlook section there is an interesting article on memoir by Jonathon Yardley, titled Shelve them under navel-gazing. More on that article tomorrow, but you can pretty much deduce his opinion and slant on the topic by the headline. (Definitely worth a read.)
I have written numerous memoir pieces, three of which have been published in literary magazines, and as a result have accumulated some insight into the subject. There are several questions you should pose before getting started:
1) Why am I writing this? (why are you?)
2) Should I be writing this? (worried about offending someone?)
3) Am I a good enough writer?
4) Will it be published?
I would suggest that if you have a strong need to write about your life, you should. However, if you write a memoir with the primary goal of getting published, you might reconsider. Writing it and getting published are two separate things. The first you have control over, the second far less so, unless you opt to self-publish. You should write for the sake of writing (I know you've heard this a zillion times, well maybe not a zillion, but you know what I mean). Let me add that getting short pieces published is far easier than a book length memoir, and this might be a way to begin.
Here's what renowned author Barbara Kingsolver has to say: Close the door. Write with no one looking over your shoulder. Don't try to figure out what other people want to hear from you; figure out what you have to say. It's the one and only thing you have to offer.
And I would add: don't worry about getting published, that's beside the point, and will come in due time, if it comes at all.
Let me know why you want to write a memoir and the focus of the piece or book, and I'll give you a few things to think about.