As Sue said .. it is strictly a personal decision as is the reconstruction following mastectomy. I would think a second opinion as well as a consultation with a Plastic Surgeon might be of value in your circumstance. If after a couple more opinions you still, like you said, don't really want the surgery then don't do it. I see no reason to rush this and there will be another summer break next year. You absolutely must be comfortable with a decision of this magnitude. I'm NOT against it and probably would choose it for myself under certain circumstances but it deserves a lot of thought. Regards ....
It's an extremely personal decision.
If it were me, and it is me too, yes. Absolutely yes. Get it all off. My second mastectomy will be in March (fingers crossed) and reconstruction with muscle pulled from my back. My family history is loaded with ovarian cancer, breast cancer, non-hodgkins lymphoma, lung cancer and colon cancer. I am HER2 neg and Brca1 & 2 negative, but the family history speaks volumes.
On the plus side, besides having some peace of mind, another perk will be that when you're 80 you will still have perky breasts! lol