Your sophomore year, you will continue building the academic foundation you began your first year. By continuing to explore disciplines through coursework, and talking with your college advisor, peer advisors, and others, you will continue to inform your thinking about major selection.
You've probably already taken introductory courses in disciplines of interest. You may have taken several and might have a good sense of where your interests lie. If so, it's helpful to talk to the director of undergraduate studies in departments you are interested in to learn more about their majors and major requirements.
If you're still unsure about your major, there's still time to explore options through coursework and conversations with members of your advising network. And, don't assume that if you did not take classes in a department during your first year that it is no longer possible to choose it for your major. Instead, discuss your interests with your advisor- if you wish to pursue a new field, you will likely be able to figure out a way to make it work.