I was exclusively a Javascript/Python/Java programmer before jumping into Rust. If you're looking to learn a systems language with real bare-metal capabilities, Rust's safety features will go a long way towards keeping you on the straight and narrow as you figure out the concepts essential to low-level programming.
And because Steve seems reluctant to plug his own book, here's Rust for Rubyists, which is an introduction to Rust geared towards users of higher-level programming languages: http://www.rustforrubyists.com/
And because Steve seems reluctant to plug his own book, here's Rust for Rubyists, which is an introduction to Rust geared towards users of higher-level programming languages: http://www.rustforrubyists.com/