Follow what you’re most interested in and you can’t go wrong. If you don’t excel at what you like, you might have to think of another way to work that interest into your life but maybe not choose it as a major.
I knew what I wanted to do for a career but I was not sure on how to get there, so I asked my advisor a lot of questions. The undeclared advisors are very knowledgeable.
Everybody has their opinion about what to do when you get to college – join a club! Be involved! Go out every weekend! Don’t sit in your room! But not everybody is that social or energetic. Don’t get too isolated, but follow your own intuition about how much you want to do on campus besides go to classes.