If I decide that I want to be a business major during the summer before my senior year, what can I do?

Better late than never so good for you. I would research the best undergraduate business schools that are both Target schools and Reach schools and see how competitive they are to apply straight from HS. Then I would take a step back and see what the difference is if you applied as an Economics Major or Math Major. If its easier to get into with Econ/Math, I would apply to the better schools as either undecided or an Econ/Math major and then transfer into the business school like 2nd year. What matters most is that you get the degree you want at graduation not how you got there. Sometimes HS students take a Gap year or go to Community College for the same reasons. They use this time to prop up their GPAs which increases the probability of getting into their school of choice. As long as you have a goal and a strategy to get there, that's better than rolling the dice to get into the best business school right off the bat. The other thing some people do is go to a public college for 2 years and then transfer to a better college. There are many options. I would totally skip the idea of applying to prestigious business schools like Wharton, Ross, Olin, Stern, Dyson or Mendoza. Even applicants with near-perfect grades and board scores get rejected. Maybe look at Syracuse, Fordham, BYU, Miami, Pitt, UWash, UWisc, or UMass. Also, it's not too late to sign up for SAT/ACT/SAT II so if you can show a 1450+, 32+, or mid 700s on your SAT IIs that will help offset your GPA. But that means you have to grind this summer.

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