MIT is a technology school – good for computer sci, not so much for animal cruelty. They also have very tough admissions policies, so you’ll need to make sure you study hard and keep your grades up. I suggest you talk to an animal cruelty investigator in your town (maybe at the police station) to find out what you should study if that’s what you want to become.

There is plenty of time to prepare for your career – you don’t need to know everything right now. Besides, your career plans may change when you get to high school and get to take other elective courses and participate in different extracurricular activities. No need to decide today what you want to spend the rest of your life doing.