You've come a long way and we've covered a whole lot of material, so let's take a few minutes and look back at what you learned. Hopefully you feel much more comfortable about what actually goes on in a web developer's life.
You know that, though you'll learn enough design to be dangerous in the next lesson, the designer's job is often (though not always) quite different from that of the developer. You also know that you'll be developing "web applications" with some serious meat to them instead of just static "websites" but the distinction doesn't really matter much these days anyway.
You saw a demo of a complete web development workflow and it hopefully gave you an appreciation for how taking a structured approach to building websites can make your life much easier. It should also have gotten you excited to try on those skills for yourself.
Finally, you learned that the best web developers are curious, passionate hackers with a definite lazy streak and that the best way to get paid to be one is to focus on building lots of cool stuff.
The web is pretty complicated in its implementation but, at its core, it's really just a bunch of packets running around delivering little bits of information from clients to servers and back. The clients (browsers) are asking for HTML pages, CSS files, images and more and the servers are sending those files right back.
You also learned about using the browser's Developer Tools tab to inspect and debug the front end of your web sites (and anyone else's).
The command line shouldn't be too scary for you anymore. You've got a handle on how to fire up your Bash prompt and use it to navigate your file system. You've customized it the way you want.
You installed the necessary software to get this party started. Lots of these things, like Ruby and Rails and RVM and Heroku, will show up later when you start diving into the server-side stuff. Others like Git and your text editor are immediately useful to improve your workflow.
And you learned all about Git! You should be quite comfortable with the basic concepts of version control and how to get your files up onto Github. You may be a bit less sure about some of the more intermediate concepts like branching and merging and why you'd actually do these things in real life but that's okay. You'll get plenty of opportunities to use them in the coming weeks and months.
You were even able to make a pull request to a real open source repo on Github as a part of the project. You're ready.
Engineering is all about continuous learning, so hopefully all that knowledge has you hungry for more. This is just the beginning!