After almost a year of trying, I'm finally pregnant

After almost a year of trying, I'm finally pregnant! I am ecstatic, but the first thought that came to mind (after holy cow!) was how am I going to tell my sister. Less than a month ago she lost her son at 29 weeks of pregnancy. I was with her through the whole thing and our entire family was rocked by this tragedy. I'm planning on waiting a little while to tell her and everyone else until I go to the doctor, etc. but I feel so guilty. Why her? Why me? I can't help but think that her child was taken away so that I could have one. Certainly not a fair trade. Nonetheless this is the hand we've been dealt. I have prayed for this day to come and it's here. Now I'm praying that this news doesn't destroy my sister all the while it makes me full of joy.