My cousin was diagnosed 11 years ago at 11 years old, I was diagnosed 4 weeks ago at 23 years old. The differences between our reactions were night and day.
She went through the denial, the rage, the confusion. She was just starting secondary school and just wanted to be "normal". Hormones certainly don't help! She was upset and anyone and everyone was a target! She had it and we didnt, how were we meant to understand?
I'm older, I understand the condition and the importance of controlling it. Ive gone through school and uni, the heavy drinking years, getting my driving license and buying my house. And THEN I get hit with it. After the 'hard stuff' is over. So yes I've been upset, but being older I think I can control my emotions more.
My cousin wouldn't have dreamt of speaking to her mum or dad, but as I am only 1 year older we are close and she spoke to me and her other friends sometimes. Does your daughter have someone she can open up to? Maybe ask her if she would like to chat to someone else? No offence, but as close as mother and daughter can be she may not want to tell you some of the things going on in her head! If she's able to release her emotion elsewhere then that might help her. Just a thought!