Hi! Welcome to the forum!
It's definitely normal to be scared, but that's what this forum is here for! If you have any concerns or questions, you can bring them here for help and answers. I was diagnosed at sixteen, and had no real support system at home. I feel like this forum could have helped me tremendously.
I wouldn't worry about your lifespan. You should be fine in that department! Just make sure to stay on top of your treatment and communicate well with your doctor, so that your long life is as pain-free as possible.
As Angrybird asked, how are you feeling?