Good lord.
As someone that didn't put the amount of effort I could have into high school, I can guarantee you that you'll regret it later.
In the modern economy you will not be able to get a decent job without a college degree, and you'll have a hell of a time getting into a decent college without good standings in high school. With crap grades your best bet will be community college (getting the absolute best grades possible) and transferring to a good college/university after that.
Entertainment is a perfectly respectable career goal, but the reality of the matter is that it's very difficult to make a decent living off of magic. There's anecdote after anecdote about this from the professionals. I was listening to an interview with David Williamson a couple weeks ago, and he mentioned that after he won some gold medal for close up magic, he went home to wash dishes at a local restaurant to pay rent. For every successful magician you see out there, there's probably hundreds that would starve if they depended on magic for money.
So put down the props. Do your homework, study, get good grades and go to college.
You'll thank me (and everyone else giving this advice) later.