Go on line. Query: What publishers publish memoirs.
Better yet, attend some writers conferences, and there are LOTS of them out there. At those conferences you can connect with publishers and agents. For all I know, there are conferences specifically for memoir writers.
Try to find a local writer's group, one that includes people who are writing memoirs or family histories or the like. You won't do well in one that is composed of science fiction writers, or writers of children's books. You might want to post something on line in your area, looking for people like you.
If you are thinking of self-publishing, think again. People who self publish do not have any conception of how much goes in to editing and finally publishing a book. It's not at all like the last time you wrote a paper in high school or college. Which is why I tend to avoid self-published books. They are usually crap.
Meanwhile, keep on writing your memoir. It will probably take a lot longer, and go through more drafts, than you realize at this point. But hang in there.