Mistakes happen. You can tailor your opponent AI to something that presents a reasonable challenge for whatever your skill level is...rest assured they'll make plenty of mistakes themselves.
You can customize the length of the games, too. The smallest, sparsest maps can be completed in a couple of hours, while the largest can provide weeks of play time. It's all up to you.
For a newcomer would you recommend the smaller maps so that I can grow accustomed to it? That sounds rather appealing anyway. From the sounds of it this game seems unlike anything I've ever played before, which is kind of what I'm aiming for in a game (I've found myself getting bored of just playing the same old stuff constantly).