There is no way to tell where you would place in a meet, because there are so many different federations and levels of meets. You might walk in and take 1st place because you're the only one there, or you might wind up in the same class as a couple of world-class lifters. So for the first couple of years in powerlifting, you can't let where you're going to place determine whether or not you enter a meet. Once you get used to the sport and start being able to put up numbers competitive on a national level (which you may be closer to or farther from than you think), then where you place starts to matter a lot more.
I think the best thing you could do once you get back is go attend a powerlifting meet (or two or three) in your area. Going to a meet will teach you a LOT about how they are run and what you can expect. Talk to people at the meet to try to clear up any questions you have, and, more importantly, try to find powerlifters there that lift near you. Getting with a group of powerlifters is the absolute best thing you can do for getting better at powerlifting. How you train, how you eat, how you rest, how you supplement all don't mean jack shit compared to lifting with older, more experienced lifters.
Once you have been to a meet or two, and hopefully once you have lifted with some like-minded individuals, then you can find a meet to do. Your only goal in your first meet should be to perform the lifts properly and finish the meet. Some people have misconceptions as to how the powerlifts are properly performed, and going to meets, reading the rules, and talking to other lifters will clear up any questions you have about this.
You will probably be surprised with how you perform under meet conditions. Once you learn what to expect, it will be easier to plan and make progress.