I have a Daughter your age with Crohn's. I know how you must be feeling right now. First of all, you need to know that the diagnostic phase is the toughest time. There's so much anxiety, as we all would want to know what's going on.
Once a firm diagnosis is obtained, then you can get on a treatment plan. You need to be able to have confidence in your Doctor and GI. There are numerous levels of severity with this disease, and also numerous medications. You may find that you have a mild version, and get by with a simple medication.
Try not to worry. You must be very mature and assertive, since you were able to find this website and post your story.
The other thing is, this website is a tremendous resource. There are alot of great people here that are willing to help you out. Continue to post questions, and check out the new videos at the home page.