I wrote an eBook at 17 (I'm 21 now)

Ok here's the thing.
At age 17, I was sad, alone and bored. I was really into internet marketing because I wanted money and I had come up with a great idea (that I never put to use). So I began researching ways to market to people, both online and offline.
What astonished me was the lack of information regarding the way people thought when making a purchase.
So instead of going with the idea, I began writing an eBook on that topic.
I spent an entire summer researching and writing it. It was my baby. It was genius, and most of all, it was simple.
But then, after finishing the book, I realized that I had no authority and no connections and figured the eBook would never sell.
Then I forgot about it.
Now at age 21, I came across it, reread it and am amazed that I wrote that at age 17. It has information that you can't find anywhere, really, and delves into the minds of the customers so deep, you'll be able to distinguish which type of customer they are and able to predict if they will buy or not after a couple clicks.
I've shared it with a few business owners I know and they asked to keep a copy for their own reference. I guess it's that good.
I would list some of the chapters, but to protect the product, I will not.

My problem is: I still have no authority, nor experience in this field. It was just passion and interest that lead me to write the book.
However, I feel like I can still make money off of it. But I don't really know how.

I know I wrote a book about it, I still want to ask experienced marketers.
I have a couple questions:
Based on what you know, how much should I price the eBook for? (98 pages).
Who should I market it to?
How should I market it?
Where should I sell it?

I've had ideas such as selling it on Fiverr, or on here, but I want to realized the potential of an eBook the 17 year old me wrote almost 5 years ago.

Thank you.
And thank you for reading this, sorry it's so long.