Good for you for expressing your concerns, it is natural to get nervous before surgery and wonder what you did the day after surgery...
However, I had a BMI of 30.8 and no co-morbilities. I LOVE my Sleeve and like Mac just wish I had done it sooner. I struggled for so many years, losing and gaining, losing and gaining more. For the first time since I was a teen, I have control of my weight, I like my body, I love life, I am strong and confident and look great... (blush...)
I am so happy I was able to go to Cancun, Mexico where they would do surgery on me with such a low BMI, because I am so tall I still will end up losing about 90 lbs in total, because I like to be extra thin, but in Canada when I inquired years ago, he basically laughed me out of his office. After that I lost 74 lbs with Atkins and kept it off a few years, or gained it back slower than usualy is probably more accurate. When I gained it back that time, I said that was it, I was done with dieting, and I just slowly got heavier and heavier and more and more miserable...
Having the Sleeve has changed my life! Go for it!