Dan
Don't worry is about the most useless piece of advice any parent can ever be given about any of their children and right now singularly inappropriate.
But the most important thing I think I can offer is - don't either of you blame yourselves, whatever else you do or don't do. It's totally indiscriminate where it decides to land and there's diddly squat anybody in the world could have done to stop it. Neither can you take it instead of her, so don't waste time on that thought either!
Most important thing now is to APPEAR as if you are coping to your daughter even if you fall apart when she isn't around. When adults are diagnosed we all have to go through a weird period of grieving. I'd got through that and waved goodbye to it decades previously without realising that was what it was, until someone pointed me at a piece called 'The Five Stages of Grief' - you can actually chart your progress coming to terms with it, just by reading that. It's reassuring!
http://www.businessballs.com/elisabeth_kubler_ross_five_stages_of_grief.htm
But the Ragnar Hanas book is a must-have - my DSN has her own copy in her office and uses it frequently to show patients of all ages (I'm 64 !) certain things she's trying to explain - Ragnar often explains much better. Or, just a different way of saying the same thing. Anyway, just trying to demonstrate that it's a book that NHS diabetes clinics approve of.
Also Diabetes UK provide brilliant info for what to do about school - one pack for parents, one pack for school - and it should be a 3 way conversation there - yourselves, school and your little girl's DSN (Diabetes Specialist Nurse) or actually once it's sorted - a 4 way conversation cos your daughter has to be happy with whatever is arranged, doesn't she? Have a look at
http://www.diabetes.org.uk/Children-and-diabetes/
Lastly for now I was dignosed at age 22 just before the 1972 Munich Olympics. and here I am, no complications. Pumper Sue on the forum was diagnosed as a child, is younger than me, but has had diabetes for a fair bit longer than I - and no complications either. So don't despair !! It ain't all doom and gloom.
Good luck, and {{{Hugs]] to all of you!