It really doesn't matter what happened to someone else - your situation is your situation. Your age, your fattest weight, the character of the skin in a particular location, your sun exposure, your smoking history, your skin color, your genetics, your luck.
If the risk of getting sagging skin is something you would seriously consider as a deterrent in making your decision whether or not to have bariatric surgery, you're not yet ready to make that decision.
Also, there is NO association with the DS in particular with skin sagging, other than that the DS is more effective so there is more weight loss -> saggier skin. It also has NOTHING to do with how fast you lose the weight.
And - really? You can work out all you want, but the only way that is going to affect how your SKIN fits your body is if you bulk up to the same size you were when you were fat. There is NO exercise that affects the skin.
