IDPA, USPSA, IPSC, MULTI-GUN, etc. are all games. Competition. You can tell they are competitive games because they keep score. I really enjoy them and have for several years now, but they are not self defense training, etc. You will learn to shoot safely, to shoot under pressure, and have a great time.
There are a ton of people who teach self defense training, proper technique, and how to do better at these games. I think you will have a lot of fun as long as you take them for what they are. AND, take your equipment with you when you go to watch.
my $.02,
George