Nice :) I'm not a React person, but I've done a bunch of beginner-level tutorial writing (including a book). I like your writing in general, but to be more critical I would say

* Combine the parts - the first part is really short and doesn't stand that well on its own.

* Make it less about you. As a reader, if I want to know about you I'll stalk your 'about' page or something. I find the info about why you wrote the tutorial and the overly modest "this is just what I think" type statements get in the way of the actual content.

* Instead of the intro about you, I would add an intro about the technology you're using. What are the alternatives, and why are your choices better?

Otherwise keep up the good work :)