(((Beta Rose))) I am so sorry to hear about your diagnosis. I definitely understand how you feel. When I was diagnosed at 21 it turned my world upside down too.
You said you were prepared to get it later in life... does diabetes run in your family? Were you diagnosed with type two?
I know that the initial diagnosis is hard, but trust me, it DOES get better. I started out on 1500 mg a day of oral meds and am now off them completely! It's amazing what a little diet and exercise can do! I managed to drop my cholesterol more than 30 points in six months just by changing my diet and exercise regimen. My HbA1C is now at the level of a normal, non-diabetic person.
I know it seems like a diagnosis of diabetes is the end of the world, but eventually you do adjust (a period of denial is definitely normal -- trust me), and you figure out the best way to manage everything. The hardest part for me was learning to take care of myself, even though I didn't feel "sick." It's hard to think about 20-40 years down the road sometimes! My grandmother helped tremendously though. Sadly, she has suffered diabetes complications because she hasn't taken the best care of herself, and seeing that has helped me to make positive changes in my life.
My advice is to give yourself plenty of time to grieve and be angry about the diagnosis, and then go out and get a bunch of books on diabetes, research on the internet, and become an expert on how best to take care of yourself. After a while, you do get used to it, and it isn't as hard as you initially thought it would be. If you ever want to vent, feel free to PM me.