How hard is it to switch out of exploratory studies after 1st/2nd semester?

I was accepted to Purdue exploratory studies, but am not sure if I want to go. My question is where can I find more info on declaring a major once I decide what I want to do. I love Purdue and would love to go here, but I am scared that if I go to Purdue and do average then I will be stuck having to major in something worthless while paying out of state tuition minus a $5500 scholarship.

I see that to transfer into finance and economics, you need to have a minimum of a 3.0 and just get better than a C in calculus. For math and statistics, a 2.5 and C in calculus.

It doesn’t seem too hard, so if I get a 3.0 and a B- in calculus would I really have a shot at transferring? I know I can do better than that though, so what would it take to transfer into these?