Bluespade, what nationality are you? Pardon me if I'm being too forward and we can all be logical and have are 2 cents here and have a downright Disney movie moment which is what we all want. BUT, your heritage is key to figuring out your situation. If you have parents who were raised in Asia, I almost guarantee you that if they still hold their traditional values, almost all this advice so far applied would make your situation worse. Questioning their authority will make you look stubborn and incompetent in their eyes. If they are second generation then maybe you'll have a better chance?
Judging by your grammar I'm going to assume you yourself were at least born in America or an English speaking country. Which brings about the issues of your environment. Perspective is everything as Draven has mentioned and if you don't live in a great environment where drugs and sex are prevailing issues with your peers, this can be your excuse to them as an outlet to breathe. However if you're in a well fed white suburban neighborhood where those are less of a visible issue to parents then maybe showing them good grades will help as it shows that you can balance your priorities and your passions. You're 15. Take advantage now to live "silly fantasies" lest you lose your creativity when you grow older. Practicing cardistry shows discipline and passion, lessons that are not usually taught in school. And it's questionably more educational than your dad's sports game.
Judging by your grammar I'm going to assume you yourself were at least born in America or an English speaking country. Which brings about the issues of your environment. Perspective is everything as Draven has mentioned and if you don't live in a great environment where drugs and sex are prevailing issues with your peers, this can be your excuse to them as an outlet to breathe. However if you're in a well fed white suburban neighborhood where those are less of a visible issue to parents then maybe showing them good grades will help as it shows that you can balance your priorities and your passions. You're 15. Take advantage now to live "silly fantasies" lest you lose your creativity when you grow older. Practicing cardistry shows discipline and passion, lessons that are not usually taught in school. And it's questionably more educational than your dad's sports game.