I'm a sophmore in highschool and I'm thinking about a fighter pilot career, but I really don't know that much about the requirements. And I don't know if it's even possible for me now because of several things.

My grades were good (not great) last year, but this year they're horrible becuase I was in a rather negative state of mind for most of the year and I didn't really care.

I'm not good at stuff like algebra, but I'm fine with basic math.
I heard you have to have a real high GPA and take a lot of math to even have a chance at being accepted into an academy.

So my first question is: Is it worth my time to raise my grades and what are the chances of me getting accepted if I do?

And exactly what are the requirements for being a fighter pilot? I hear they're different depending on what military branch you're in, like Navy, USAF, the Marines, etc.