Well, I was not as young as you are, for sure. I was 36 when I was diagnosed. We do have gals here who were much younger than I am, and have been hanging around for a long time! Lori and Annette were both younger than me when they were diagnosed, and they've each got a number of years NED under their belts as well.
My mother had died at 45 of cancer, so I remember thinking about the same way as you...that this was just the beginning of cancer, that they would just keep having to take out parts until there weren't any parts left that weren't vital. But here I am, almost 15 years later, still NED (no evidence of disease). I just went for a checkup with my oncologist, and all my bloodwork was "perfect." So breast cancer doesn't have to be a death sentence. And we'll still hope for the best, even if you're preparing yourself for the worst here!
We'll cross the bridge of husbands and family and kids if we have to, but for now, just take it one day at a time. Most of the questions you ask really depend on the answers you get from the surgeon. I know that it's not easy to let your mind race ahead to the "what if's," but 50/50 is still equal chances that it's not cancer.
"There's a difference between a philosophy and a bumper sticker." --Charles Schulz