How do I know if I qualify for a gastric sleeve?

I need a professional opinion to help me figure out if I'm a good candidate for gastric sleeve surgery. I live in a small community quite far away from any major city center so I don't have ready access to a medical clinic. I'm 5'6" and currently weigh 263 lbs which gives me a BMI of 42 (I think? I hope I did it right!). I have been steadily gaining weight since my last pregnancy 2 1/2 years ago, can't seem to lose weight when I do diet (I've tried several diets but, again, because of where I live, my options are limited and there's zero support for my problem though there are many overweight people in this community) and I'm so scared that I'll just keep gaining and then won't be eligible for anything but the most drastic weight loss procedures. I've got so many questions and concerns but no idea where to begin. I guess I'm beginning here but a doctor's input and guidance at this point would make a big difference in my next steps. Thank you in advance for your time and assistance.