Many on gun forums rip on IDPA a lot referring to it derisively as a "game" rather than training - and they are correct, it is a game and not real training. However, I definitely find it better practice than simply standing static at my local indoor range and shooting at a bulls eye as you are shooting from the holster, moving while shooting, practicisng reloads (though these often result in procedurals (penalties) in one way or another for me, shooting weak-handed, etc, with a form of stress added, even if it is more like stage fright than life-threatening stress.
I went and watched a match first before just jumping in, I'm glad I did though many just jump in and that is fine. For your first match or two my advice is to go slow and concentrate on making your hits and try not to be Bob Vogel. I am still relatively new and I still commit a lot of rookie errors like dropping mags with rounds still in them, or moving while reloading, or shooting targets out of order. I am still new enough that my brain turns to jelly as soon as the buzzer goes off, and I enjoy every second of it.
For now, I think of myself as competing against myself rather than others.
It is some of the most fun I've had shooting in awhile.
"Remember, the people on the Internet are just like you - ignorant, delusional, and dangerous."