The original story idea sounds fairly standard to me as others have said, though I've never been a particularly huge fan of physical regression nor older male regression, so it might just be a matter of tastes. The pedophile thing is potentially creepy though, I wouldn't include it in a book about physical regression, particularly with online transaction regulations being as difficult as they are on fetish topics. edit: I should also add that 'standard' isn't bad, it just depends on whether it's well-written. I've bought a few ebooks which might have been 'standard', but were done well enough that I liked them better than some innovative things.
As for users posting some of their content in paid formats, it's been that way for over 15 years of abdl
on the Internet
. I've sold two things because they took months of my time to make and I honestly can't otherwise afford to do them, but people seemed fairly happy to buy them, and nobody is forcing anybody etc (though I feel that my last release wasn't very good, so am working on something even better).