Any idea can become a book. It’s how you write the story that makes a book interesting.
When you say book, are you fictionalizing the tale or is this a non-fiction business book?
If it’s a business book, your readers will want advice on how they can grow to become an entrepreneur. While your story might help pull them in, readers will want a plan that is specific and actionable that they can follow. Make some notes. Start journaling. Write down the steps you took along the way. You will be surprised to discover details and interesting events that you buried in the back of your mind. But, even if it is a business book, use your story to keep the reader interested.
If you want to fictionalize this idea, you will want to create an empathetic protagonist working odd jobs who has some desire/ goal to one day own their own business. And then plant some insurmountable problems in the protagonist’s way that will prevent them from reaching their goal - until the end when they finally make it happen.
With the fictionalized version, you don’t have to stick with the truth. You can use your story for inspiration but change the details as you need for the sake of the book.
In the meantime, a journal will be your best friend. Write down every idea and let your mind go wild. This is also a good time to study the art and craft of writing. There are plenty of free online resources.
Best wishes on your writing journey.