You’ve been given a lot of good, sound advice here. The only thing for you to decided now is what are your goals. You said you want to compete. I assume that means you want to win or place as high as you can against other lifters.
The next decision you will have to make is what federation you want to compete in and that’s a whole other thread altogether. If you want to use single-ply gear and desire to compete in a drug tested federation I highly recommend the USAPL.
There are a few federations that offer a “raw” category which means the lifter is not allowed to wear supportive gear. However, even in those federations A BELT IS STILL ALLOWED. A belt will give you an advantage over those that don’t wear one in most cases because the belt is a form of supportive gear and will give you a higher total.
If you want to be competitive with other lifters in your category, you want to win or place in the top 3, you’re a new lifter who desires some awards to have around the house to show your friends (trophies, plaques, medals) and if you have the desire to go to the top such as national or international meets (the IPF) that allow gear to be worn then you will certainly need to buy a belt and learn how to use it. Should you not decide to go with a belt then understand what your up against and don’t complain about it later.
There is so much debate and static regarding the use of gear and raw lifting. If you’re interested you can read the last installment of this debate on a title called “Raw Powerlifting” that was a week or so ago on this forum and you’ll see what I am talking about.
You’ve got many choices even within powerlifting on what path you want to go down. It’s all a matter of what you want. After a few years you can change things up or go a different direction in powerlifting to make it more interesting should you desire. Good luck with your training!