Im a junior in high school right now. My dream is to become a cardiac surgeon. how can i achieve that goal?

my high school career has be okay. I always p all my cles, but have struggled with Math. My current GPA is an 3.0, im really not the type of kid who took high school very serious until now. My teachers have always told my parents that im a smart kid, who just doen't give 100% to everything he does. But as im getting older im realizing that school is life, meaning an education. So this summer im hittting the books hard, work on my vocabulary to prepare for college. i am planning to start at a community college, then transfer to an University. so my question is what should i do in order to fulfil my goals, and also about my math would it get better as im getting older in college? Thanks