I think there are two factors for making a career decisions:
1. You like that career
2. That career is useful in future (financially)
If any 1 of these is left out, you may don't like what you are doing or you may <em>have </em>to do something you don't like for a living (along side with your main career choice).
Firstly, you should research the following things:
1. How hard it is?
2. What future choices does it offers?
3. How much competition is there?
4. Will you be able to compete with the other students who have chosen that career?
5. Do you already have some knowledge about it or you have to start from scratch?
After answering these questions, you should be able to choose your career.
Thanks.
P.S.: I am not some expert, I just know a little. So, there may be some points that I don't know or forget to mention.