My sister in law just found out she has cancer

A few months ago my sister in law told me that she was having some issues with her health. But she had a baby in August so it wasn't like I thought much of it. And Stephanie tends to not make a big deal out of things. So a few days ago her doctor scheduled a colonoscopy to be done. We got a phone call from my father-in-law yesterday saying that my mother-in-law went up there two days ago and that she called him and told him that they found something. They were doing a biopsy on it and they'll let us know.
My husband called this afternoon and told me that they said it was colon cancer. I just can't get over it. She's 32 years old and just had a baby 3 months ago and have a little boy who is turning five in five months. It's just horrible. She's a wonderful, young person with a good life and no history of drinking, smoking or eating poorly. It just makes you think, why? Why would this happen to HER?
We're still waiting to hear what stage she's in and what the plan of attack is going to be. I just feel so bad for her.