Ok, so, you are not alone! I had the same thing when I was 14!! I didnt have stones but instead my gallbladder was not functioning or contracting! Mine was 11% out of 100, and it only got worse. I had the same concerns so I waited until i was 16 and it was miserable. The truth is, when it has to do with the inability of your gallbladder to function, it cant get better. Only worse and increasingly painful. Eventually it might get to the point where you can barely eat at all. I am 19 now and my scars are unnoticeable. I did not gain any weight and the surgery went fine and I was finally able to live again. I won't lie to you though, I still have to watch what I eat, the surgery isn't a miracle worker but in your case i think it might be necessary.
As far as weight loss goes, I don't think this should be a factor of your decision. Yes, you may lose some weight because you can't eat after surgery, but thats just as temporary as anything else. Since I had gallbladder problems, I changed my diet drastically. I stopped eating fatty foods and it really helped. When your gallbladder isn't working, it has a really hard time contracting, fatty foods make it necessary for it to contract, and when it cant, all the bile gets stuck an built up. this is why you are having so much pain.
Yes, surgery is scary, but those doctors know what they are doing, the recovery time is only about a week or two, and yes, it will hurt, but they give you good pain killers for that. I have 10000 more info about it if you need it. Just let me know!
The only way to treat gallstones is a gb removal.
Some people gain weight after gb removal, since they don't feel pain after the meal anymore - and they stop to avoid eating.
There is no direct link between gb removal and weight gain/loss. You gain weight as much as you eat. If you were avoiding fatty foods to avoid pain, then just keep this good habit after gb removal.