I'm in a similar position. This spring I topped out at 226 pounds, though I'm only 5'9". I felt horrible and never had any energy. I haven't joined a gym yet, I'm going to. I just turned 29, and I have been overweight for 10 years, and I really don't like it. I've lost 20 pounds since May just by eating better. I've never been a cardio person, but I realize I must pick it up. I'm not getting any younger. My advice for you is just to go in there, and try to just stick to a program. Don't over do it, because then you'll give up. Start light, and work yourself into a routine. Perhaps there's a gym trainer there who can help you out, but it'll probably cost you extra. My plans for joining a gym are simple. I'm not looking to get cut and ripped up, just get into my weight range according to my age and height, which is around 170 pounds. So if I make it to 180, I'll be happy. I am set on 2 things only: treadmill and weight bench. We have a stationary bike at home, but it's too small for me and it's very uncomfortable to ride. But it is helpful, if you stick to it.
Another thing you can try is the diet program NutriSystem. It worked wonders for my ex GF's mom, she has lost 80 pounds since January, and she just ate their stuff and some extra vegetables and fruit on the side, and rode that bike for 30 minutes a day. She is also diabetic. But it costs about $300 a month (depending on your plan) and some of the food doesn't taste very good. It also requires strict discipline. You cannot eat anything other than what's in their plan. If you can do that, it'll probably work for you.
I'm to the point where I could not care less about what others think about my body. Let them stare, I don't care. Granted, you have a little more than I do, but the psychological hurdle is the first one you have to clear. And besides, all those "beautiful and perfect" people were most likely overweight before they got there. So if anything, some of them might actually have some words of advice and encouragement. As for gear, depending what you plan to do for exercise, all you should need are shorts, a T-shirt or sleeveless shirt, and maybe weight lifting gloves and running shoes.
Another thing, you might want to go with a trial membership first, see how you like it and can you fit a regular exercise regimen into your schedule. Me, I'm going to a gym where I can pay $20 per month, not any other fees. Of course, if I pay for 6 months or a year in advance, it costs less, but then I'm committed financially. So I don't do that. I go by the month. It's convenient.
So just figure out what type of exercise you're comfortable with and is safe for you, and start with that. Don't force yourself. Start light, and work into a routine, and gradually increase and change the routines. Also, change your diet a bit. Start eating smaller portions, and make sure you include all food groups. Also, and this is just my personal thing, I make sure to drink at least 1 glass of milk and 1 glass of OJ every day along with several bottles of water. Hydration is very important. Don't completely deny yourself "bad" foods, just gradually cut down. It works better. And keep track of what you're doing. Trust me, it won't look like much from day to day, but if you do it right, you can look back in 3 months or 6 months and see a real difference. The first step is the most difficult, it took me a long time to take it as well. But after that, everything gets easier. Your self confidence gets a boost, your body feels better, and things start looking up.

Good luck!