Just got this game, started a Peaceful world just to practice mining and crafting. Hit a motherfucking HUGE cavern complex while digging at my first outpost. If it weren't peaceful I'd probably have been killed by a creeper dozens of times by now, but even with all the time that would be otherwise spent dying freed up, I don't think I'm anywhere near finished exploring and lighting up this complex. But I have a lot of iron ore and coal, so no worries there!
Welcome to Minecraft, here's your free wooden pick and autism.