Pagination in Jekyll 3 not generating pages - ruby

Question

I'm encountering an issue with Pagination as I make a website; it would appear to be a nil variable, according to the command c 'paginator' when using this plugin: https://github.com/octopress/debugger
In addition, if I replace "site.posts" with "paginator.posts" in blog/index.html, I get no posts. I am running on Ruby 2.4 and Jekyll 3.3.1.
My setup is as follows:
_config.yml
gems:
- jekyll-autoprefixer
- jekyll-paginate
plugins_dir: [jekyll-autoprefixer, jekyll-paginate]
paginate: 3
paginate_path: "/blog/page:num/"
include: [ "_pages", "_posts" ]
_pages/blog/index.html
---
layout: page
title: Blog
subtitle: Blog posts
permalink: blog/index.html
---
{% for post in site.posts %}
<h1 class="post-title"> {{post.title}} </h1>
{% endfor %}
{% debug %}
<h1 class="post-title"> {{ paginator.total_posts }} </h1>
Directory Structure
├── Gemfile
├── Gemfile.lock
├── LICENSE
├── README.md
├── _config.yml
├── _data
│   ├── team.yml
│   └── template.yml
├── _includes
│   ├── about.html
│   ├── clients.html
│   ├── contact.html
│   ├── css
│   │   ├── agency.css
│   │   └── bootstrap.min.css
│   ├── footer.html
│   ├── head.html
│   ├── header.html
│   ├── js.html
│   ├── modals.html
│   ├── nav.html
│   ├── portfolio_grid.html
│   ├── services.html
│   └── team.html
├── _layouts
│   ├── default.html
│   ├── feed.xml
│   ├── page.html
│   ├── style.css
│   └── team.html
├── _pages
│   ├── architecture.md
│   ├── blog
│   │   └── index.html
│   └── team.html
├── _plugins
│   └── hex_to_rgb.rb
├── _posts
│   └── 2017-05-24-test.md
├── css
├── feed.xml
├── index.html
├── js
└── style.css
(Most files removed for brevity)
Thank you for any help!