Hi, I'm also a low BMI (31.4). Have tried multiple diets and exercise combo's etc, but nothing sustainable.
Now, I have hypertension and borderline diabetes so I think it's worthwhile for me.
I suppose you need to ask yourself whether you're doing it just to be slimmer (and why do you want to be slimmer)? or is it health concerns as well.
Although, the risk is low from a VSG there are still complications and failures; also the cost...