Answering a question like this always comes down to personal opinion and experience, but here's my two cents.
Few things are more contentious than how well programming languages perform, but I think the most accurate general answer is one I saw on Stack Overflow a few weeks ago: It depends on how much money has been thrown at making it fast. Most of my personal experience is with C++ and Javascript, languages which have had tons of money thrown at them, and performance has never been an issue for me (except when I did something stupid). My suspicion is that Python is close to the same level, but that Golang probably isn't. These days there really isn't an inherent performance difference between compiled, bytecode'd and interpreted code. However, there's nothing stopping you from throwing together a little benchmark that represents the kind of expensive code you expect to write.
I've never felt that there was a huge gap in learning times between different languages. Once you learn a single language properly (ie, read a book or two cover-to-cover so you know several of the pitfalls and best practices, not just enough to hack together a Pong clone) it's not all that hard to learn any other language properly in a relatively short amount of time. If we pretend functional languages don't exist for a moment, most programming languages these days consist primarily of the same C-like syntax and idioms everyone knows already, and most of the stuff that really matters involves making decisions about abstract data structures and algorithms that are mostly language-independent.
Note on my background: C++ was the first language I learned properly, as part of my computer science degree, and after getting my first real job as a C++ programmer... I learned Javascript in a couple months and have barely touched C++ since, since I like UI code and that's the language my company uses for UIs.
P.S. Since you appear to be asking about SFML bindings, note that how good, active and up to date the bindings are is probably far more important than the languages themselves. This you'll have to check for yourself.