I got sick when I was 15. I am now 36, have had at least 6 different GI's and to date I still don't know what I have. I have been told UC, CD, and IBD. From all the research I have done, I am convinced I have Crohn's. No doctor has said definetely thought that it is indeed Crohn's. I have even had the Prometheus test done, twice, and it is inconclusive.
It is weird in this day and age with science as advanced as it is that it is still hard for doctors to diagnose IBD.
My whole point is don't worry or let it get you down. There is a big difference between Crohn's and Colitis so at least they can hopefully tell between the two there. If not, there are some drugs that are used for both so hopefully they can help you also.
Good luck.