Before we really start this course I want to cover a few reasons why Minetest is the right option for you.
Minetest is free, and requires no licenses which makes this course infinitely scale-able, and great for the classroom.
Minetest can run on older hardware meaning you can use whatever you have sitting around without having to spend money on new hardware.
Minetest has a large community of modders that willing to help people that politely ask for help and explain the problems they are having.
No special software is needed to write mods, all you need is a plain text editor, and when changes are made all that is required is that you restart the Minetest world that you are running the mod in. No compiling required. Additionally you don't need to make any changes to Minetest to be able to use mods, just place a mod in the appropriate directory and launch the game, the mod will be ready for you to use.
Lua is powerful and fast language, it's easy to use, and is used in many video games, meaning that you'll be able to take the knowledge of lua with you to other platforms and reuse it. Lua is also used in other non-game applications. The knowledge you gain from learn any programming language can help you understand and more readily pick up another language.