First of all I would stress too much about it :) Unless you have vocation calling & want to be a Doctor or a Lawyer for example, whatever you start studying might end up being far from what you are going to work on. Also, always remember that a career is very rarely one block of being within the same Industry at the same types of positions for 40 years. You will move between different Industries, companies, cultures & roles and learn along the way.
Most actual jobs that exist out there you have no idea what they mean & what they are when you are at the University:)
If you really have no idea, I would try to remain as generalist as possible & enter fields when you know that the demand of the Job Market is high. I would also try to understand better what I actually like. For example if you are tech-savvy & like maths, maybe lean to code & become an Engineer ?
In any way, you will meet more people along the way that will help you refine your choices & don't believe neither that you will be all set once you finish College - far from it. You will keep on learning, get more & more skills & people will come looking for you / you will search for opportunities.
I don't believe that you actually choose your whole career, I think that you make different choices along the way that end up representing a career.
Good luck !
Do not stress too much about your career right now. Just focus on doing well in school so that your options are open when you have a better idea of the field you may want to specialize in.
When I started university, I did not really enjoy math at all. But after a couple of semesters, I grew to really appreciate economics. I preferred statistical economics rather than other business disciplines so I geared all my energy towards economics and became familiar with the economic environment i.e. regression analysis, statistics, calculus etc.
So just keep that in mind, you do not need to determine your life right now. Keep an open mind to everything. But keep your options open!
My suggestion would be to research different careers. Where possible, if you know anyone in the career ask what they like and do not like about it.
Focus on your strengths. ( ie if you like working with people, maybe HR is a career to research)
Remember to be flexible! I started with a Business and Marketing degree. I now work in Process Improvement. All the skills I learnt in this degree all help me in this role. So any type of skills gained