There are quite a bit of people on here with lower BMI's I started at a 32 and i was so nervous for the same reason. I really though i'm gonna be judged and told i'm just being vain, especially because half of my family felt this was an unnecessary procedure while the other half was supportive.
However from the time i got picked up for my surgery, meeting with the other sleevers, being at the hospital not once was i made to feel like i was wrong for choosing to move forward. Everyone was super nice and although i was told i was small by one of the other sleevers they never made it sound like they were judging. The best part was when My Dr. told me he could tell I was going to be petite a year from now! I laughed and told him petite and me have never gone in the same sentence. I had my surgery for the same reason your having yours. I've been a yoyo dieter my whole life losing 20-40lbs then gaining 30-50lbs back. I just wanted the weight gone and to stay gone.
You got this, don't second guess your self based off of what others will think.... people will always have something to say about your choices. You have to do what is best for you and if you believe its to move forward then that means its the right choice.
I had my surgery in Piedras Negras in MX with Dr. Alvarez
Stats:
Female 5'6.5
HW:202
SW:197
CW:180
GW:125-135