Linda Ann’s Answer
No, it is not crucial to declare a major during your first year. You can stop worrying! At major universities, 70-80 percent of freshman change their major after the first year. Since every university has "core requirements," many of those core requirements are generally taken in the first two years of college. What I'm saying is this: you won't be losing time or wasting time if you aren't sure. Sample some of the course work that you THINK might be of interest.
ALSO, the academic advisor to whom you will be assigned will help you to navigate both the core requirements and make some recommendations to you about "how to decide." The Career Counseling Office (assuming that your college or university actually has one) might be of some assistance to you in the decision making process as well. There are many resources that will be available to you once enrolled.
ENJOY the exploration process.