Convince my parents to get me iPhone!! Help please?

My birthday is coming up soon and I really want an iPhone 4 from verizon as a birthday present from my dad. My mom's getting me a MacBook so I don't wanna ask him for that as well. Anyway I offered to pay for it and the monthly plan but he's still not sure. I have enough money to pay the $30 a month but not for mOre than a year or two. I'm only twelve so I can't get a job yet but I still really want an iPhone 4 from verizon. Please help me to convince him thanks so much!!