And I think that you and GitHub went through the stages of life together. They probably weren't exactly parallel, but I bet you measure and remember your life through GitHub's life to some degree, along with the projects you had there.
There's no question that with your drive and acumen that you could build the GitHub that you both had and want. It might be your next chapter.
Journey through Genius is an absolutely fantastic book. I took History of Math from a professor in undergrad who had a conjecture named after him and this was his choice of textbook (along with a few other materials) for the course.