Welcome to MR, D. B. Henson.
We love to welcome and support authors that join in and participate in our forums. Congratulations on your book.
I don't have a Kindle, so I am not able to purchase it (I also don't read on my laptop so Kindle for PC is not an option.) I believe calibre will not format shift if the book is DRM infected.
Have you considered publishing on smashwords? If it is on smashwords people without Kindles (those with Kindles can get the mobi format there) and those in other parts of the world may purchase your book.
I see you have found a couple of other places on MR. Did you know Kovid, the creator of calibe, frequents the forums here? We even have a dedicated
Calibre forum.
Congratulations on your book and have fun exploring and participating in our forums.