An autobiography is the story of a person's life told by that person in their own voice. The writer has to decide how to open their life story to set the tone, create interest, and establish themes for the work as a whole. There is no one "correct" way to do this, but here are a few options:
1. A traditional introduction would give the reader an overview of the full work. The writer would want to set up some background and establish the main ideas and themes for the work. This is an organized and logical way to structure the autobiography, but it may not be the best way to create interest in the person's story.
2. The writer could start at the beginning of their life. Since this is an autobiography and will tell the full life story of the author up to the point of its writing, it would make sense chronologically for the writer to talk about their birth, parents, or something else related to early life.
3. The best way to create interest in starting the autobiography would be to begin with a meaningful anecdote. This is a story from the writer's life that would capture the reader's attention and also serve as an example of a main idea or theme central to the author's life story.
There are several ways to open an autobiography. Before you start, there are two key things you will want to keep in mind. First, an opening paragraph is crucial to any piece of writing: you will want to say something compelling that will keep people reading. Second, as in biography, you want to think first about the main point you are trying to make about yourself. Definitely avoid simply throwing out a mass of facts—these facts, while important, need to connect to and support a central idea or theme.
Once you have an idea about what makes you who you are, you can choose from several tried and true opening gambits. One is to start in media res, or in the middle of the action, perhaps at a crucial point in your life journey when everything is hanging in the balance. You could also choose to start with a startling or unusual fact or story about yourself: that is a very common (and often successful) way to hook a reader into wanting to know more about you. Another idea is to begin with a descriptive passage that puts a reader into scenery of your life that is significant to you. Finally, you could begin very prosaically by explaining why you are telling your life story.
It can be helpful to look at other people's autobiographies or memoirs (a memoir is very similar to an autobiography but is not necessarily a complete life story) to see how their opening paragraphs set the tone. Some examples that can be found online are the works of Benjamin Franklin, Frederick Douglass, and Helen Keller.
The introduction to an autobiography sets the stage for the life story to follow. As such, you could use several different approaches in writing your introduction.
If the autobiography is going to be strictly chronological, the introduction would set out the initial facts. Ex: I was born on Jan. 1, 1990 at 2:23 AM. My parents knew, from my first screaming breath, that I was going to be a night owl and a challenge to control.
A flashback technique could be used if you wanted to introduce a highlight of your life, then go back and tell how it came to pass. Ex: As I strode to the podium to deliver the valedictorian's address at Commencement, I thought of all the nights spent studying, all the parties missed due to assignments I was polishing. All the work was worth it at that moment. It started in kindergarten. I got a gold star for every letter book I completed, and I loved those stars.