When starting your Terraria world, there are many options to consider. You will have to decide which evil biome you want present in your world, which difficulty to play on, and the size of the world you want to play in. These considerations are explored in these articles to help you understand what you are getting into.
When deciding which world you want, you will need to select its size- whether you want a small, medium, or large world. You will have to choose between the crimson or corruption biome. You also get to choose the difficulty level, for which the options are journey, regular, expert, and finally master difficulty. These decisions will drastically impact your world and your experience, so it is best to know what you are getting into!