The OS won't matter much in the beginning, though it helps that you're already using Linux as you likely already have Python and GCC installed.
I don't think you need a better PC than what you already have if the only goal is to learn programming, so I'd spend that money on something else.
I'd suggest you go through Harvard's CS50 if you've never been exposed to computer science before: https://www.harvardonline.harvard.edu/course/cs50-introduction-computer-science . You can audit it for free, you don't really need to pay for the certificate (which IMO doesn't have much value at that level anyway).
Also, try to get into a computer science degree if you want to do that as a career, bootcamps and MOOCs are nice additions but will never replace a real degree.