I lost my mother to it too, my condolences.
Ask more questions about the cancer itself. You want to know if it is: HER positive or negative, and whether it responds to hormones progesterone and estrogen (ER and/or PR +/-) knowing those will inform your treatment decisions a lot.
Grade 2 invasive means it's "breached" the origin, depending on where and how many you're looking at you may be a good candidate for lumpectomy/wide excision/partial mastectomy and not lose your whole breast - the difference being mainly that the recovery time is less and the psychological adjustment is as severe.
It might be familial so ask about genetic testing, depending on that result you may just want to be rid of the breast because testing positively there raises the risk of reoccurrence.
I'm struggling with treatment choices myself, but I'd suggest just taking this one step at a time. Focus on making just the surgery decision right now and the after treatment choices later, when you have the results from the surgery that will also inform you.
I hope that helped in some way. xox