I asked a similar question on here and am updating a manuscript I initially wrote for a friend six years ago.
I learnt that an autobiography is more like a journal which details accounts in chronological order made up of facts and little intimacy with the writer's own memory, which is what a memoir is. A memoir also focuses on a specific set of memories and may include references to other sources of historical information.
I am calling my book, Finding My Voice, a Memoir, though I don't know if this is accurate, because it combines both elements of an autobiography and a memoir.