Im so sorry your sister feels this way, I would just tell her she wasnt even in your thoughts when you did this. This is YOUR health and YOUR body. There is no need for her to ask like she is in high school again. Cynical family members are the reason most of our family dosent know about our bands. Im 18 (and have PCOS and a diabetic/heart diseased father) and my mother and I both were banded this past April. The only people who know about our bands are my father, brother, mom's mother nad sister (both very supportive.) We prolly will never tell any of dads family since my grandmother can be rather callous at times and my aunt has ALWAYS batttled wither her wait and to tell her would be asking for trouble. Sure there are certain ppl who suspect something but asside from my husband (when the time comes) i probably wont tell anyone about my band. This discision is because if you plataue teh cynical ones will be asking stuff like, ïs your free ticked stop working?" Ï knew the easy street was a dead end" etc etc.
So dont give up, (btw congrats on 62lbs!!!), and if your sister brings it up again telle her flat out is yoru health that was at stake so she either live with you slim or waiting for a heart attack (or some other complication of being overweight) and just leave it at that.
Good luck, Chelsey