I'm sorry to here of your granddaughters diagnosis. My GD was 2 1/2 when she was diagnosed, she was great with it and accepted it straight away, but it was so hard for me, I was very upset at the time and blamed my self.
I found JDRF very supportive and full of information, and my GD got a Rufus bear who has diabetic injection patches sewn on. I meant to say Its the Juvenile Diabetes Research Foundation, just google it.
It does get easier with time and this forum is very helpful and has parents/families of diabetic children.