How to convince my parents to let me get battlefield 3?

Ok I'm 13 yrs old im using my dads account for yahoo answers. Again I'm 13 yes old and I want to know how to convince them to get me that game. I'm raising my grades up, I'm planning to get a ps3 with bf3 this Xmas and I want to convince them to get me battlefield 3. Any ideas?|||First of all, in my opinion, age doesn't matter to me. It's how mature you are. So if you do have good grades and you don't cuss on every sentence, that's a good reason. But it your grades are all F and you're a gangster, no chance.|||Do whatever they tell you to do. You need to keep it up for four weeks after you get the game to show that your being honest and not using them to get the game.|||Promise you'll do well in school kid and maybe they'll see that your mature and can play the game with balance to schoolwork and a social life|||Begthem.|||you do nothing|||Tell them "I'm 13 and this game is only for 17 year olds so I should get it."|||no we already have anuff 13 year old on the game now :(