People switch within careers all the time. At this point, you can't possibly be expected to know exactly what you want to do. Some people come in with set goals/concentrations, but even those people don't really know what it means unless they have some experience beyond what's normal. The main exception to this might be tax law...but even that you can wait to think about until after 1L.
In the end, your career options are influenced by the interests and skills you develop in law school and the availability of positions. I know more than one person who let a great job offer make this choice for them. People do move around, so you won't get "stuck."
As for whether you can do litigation and business law...have you thought about business litigation? There's no need to pick something out now, but it was just a thought.
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