It's ok to not be up-to-date with every technology choice. No matter how smart you are, please realize that front end engineering evolves at a dizzying rate, with new hyped up libraries, frameworks, techniques, and best practices emerging all of the time. Even if you do front end stuff full time you'll go mad trying to use half of what you read about.
I think that the best way to learn this stuff is to pick a problem that you want to solve and learn the pieces necessary to solve it in a logical fashion. You'll start out with HTML, try and style it with some CSS, and then add a touch of interactivity with some JQuery. Then you'll start to have more and more code and you'll logically reach out for tools like Sass, and RequireJS and others to organize things when it becomes overwhelming. Then once you start solving bigger and bigger problems you'll eventually look into Backbone, and maybe other frameworks once you can't build a maintainable solution with what you know. Learn stuff as appropriate to solve the problem you're working on.