Lots of good advice in the posts above, pay attention to the ones from folks participating in the sport. Best advice by far is to show up and shoot a few matches before you do anything else.
One thing I'll caution is that when you show up you will likely see the "gear race" in full effect. There will be guys with all sorts of cool toys and bags and accessories that look like they would be helpful (and some of them actually are). You could easily walk away from a match feeling like you needed to go spend a crap ton of money to keep up with everyone else. There's a lot of disposable income and shiny new toy buying that can be a part of the sport. But, if you know what to really look for and which shooters to watch you can see past the gear and learn what really wins matches. IMO, here's the secrets of success in the sport.
1) Learning to hold yourself and the rifle really still from compromised shooting positions and making good trigger pulls.
2) Keeping a clear head and executing a complex shooting plan efficiently (smooth transitions, target acquisition, correct shooting order of targets, managing dope, correcting for wind)
3) Having a well prepared, accurate rifle with known dope out to distance.
None of the above hinges on how many shooting bags or accessories you buy. It's 90% a mental game, with a big chunk of that being adrenaline management. It's really, really hard to do #1 and #2 well when you've only got 90 seconds and you're amped up because it's your turn to shoot and you're being scored and everyone is watching you.
I've been able to have some small success at the sport and have gotten to practice with some very good national level shooters. There's nothing like getting your butt handed to you all day long shooting practice stages, when the only piece of gear they used was a simple bag full of sand as a rest. It helps me remember that at the end of the day buying a new piece of gear is not what's going to make me win or lose.