My friend's daughter published her book via Amazon. She done this on her own at 14 years old. I belief the online services would be simple. Give it a try.
Why work for somebody if you can be your own boss.
You could also go the route of finding a talent manager to promote your book and to receive guidance.
There are lots of ways you could get the word out about your book on your own if you do decide to go the Amazono way. For example, now with Social Media you're able to reach many and target your audience as well as with business accounts. You could also visit Barnes & Nobles and public libraries to schedule book signings and discussion groups etc.
I have two friends that have recently written books one for children and the other more of a self help type of book. I believe one went through Amazon and the other hired help. Both have been using social media to get the word out.
Why not consider self publishing? Get a good editor to polish off your story and publish it yourself through Amazon. You can track sales and reviews, and it's free to publish.
Have a look:
No one is "hired" as a writer.
Here's how this goes:
Write your book.
Edit your book - about three times.
Then you find a reputable editor to work with. YES, you will have to PAY THEM.
Once you've worked with an editor to make sure your book is awesome, then you query it to agents and publishers who accept unsolicited manuscripts.
If accepted, then you move forward into the process. Writing is an industry and requires a lot of dedication, and the ability to get a thick skin because you will be rejected.
Self-publishing on Amazon is garbage for hacks. Don't listen to that nonsense. It's like a pitcher being able to throw a slider for a strike. You gotta put in the work to play this game.