I learnt to be consistent or motivated enough to work through a project, instead of losing interest in it and starting another one(which becomes an Dr. Strange Time loop).
Also, this is my first time making a game in a game engine(I used to make Minecraft plugins with java and uploaded them to spigot), but I learnt that there's easier ways to make games, that is using a game engine instead of coding it in Java(not recommended, use a game engine, otherwise you'll pull out your hair with a hydraulic press). And I learnt a lot about the game engine I chose(Godot), and gotten comfortable with it.