I recommend that you avoid signing on with KINDLE SELECT. It's a sneaky little extra they slip in as though they're doing you a favor. It is not. For one thing, the money share you get is going to be a pittance, for another, it means you can't upload and sell the book through any other venues like Nook, Books-a-Million, Smashwords, etc. Kindle wants a monopoly on selling your title.
Read their instructions carefully, because many who are new to digital publishing may assume that Select is the normal way to do things. Their offer is worded to give that impression. For all I know they might automatically sign you into it and you have to check a box to opt out of it.
It also allows them to give your book away for free for 5 days of their choosing. That won't hurt established writers with dozens of titles, but it is of no help a writer with just the one publication.
I think you have a fine idea with this work and hope it gets out there, but be alert to the pitfalls attached! FWIW, I have never had any issues like this with Smashwords or Nook.
Some years ago (I was a newbie to digital publishing) I signed up and lost money in sales due to the Select offer. Never again!