Hi Felicia. Welcome to the forum. Sucks to be here but you've found the right place.
Please try to put guilt out of your mind. It serves no useful purpose. We are animal organisms with cells that constantly divide, live and die. One in two humans on this planet will have some sort of cancer at sometime. 5% of breast cancers are attributable in some part to genetic mutations. To the best of our current knowledge the rest are random. Sure, there are risk factors, but none are causative. We all know the people who are overweight drinkers and smokers who never have a sick day in their life, and the fit, non-smoking vegetarians who die young.
So put the what ifs out of your head, tell your daughter she doesn't know what she's talking about, and give yourself a pat on the back for getting that mammogram and hopefully catching it early. The past is done and gone, the only thing you can influence is the now, and never mind about the future, it's unwritten.
A big mantra for BC is to take things one day at a time, one hour at a time of necessary. You're in the worst bit now, the waiting for results. Once they're in a treatment plan will emerge and you'll start to feel a bit better.
Getting BC is a bit like being pregnant in that suddenly you see pregnant women everywhere! One in seven women in Australia will have BC, it's the most common female cancer. You are definitely not alone. There are lots of support services available for you and your family. Find the one that works for you and lean on it.
We are in the best country in the world to get BC (and Finland). You will be in excellent medical hands. And we are always here for you. Biggest hug lovely, K xox