How to convince your parents to give you a phone?

[Alexis]

I'm 15 and my parents still won't give me a phone They each have iPhones and they have an extra one just sitting there and they won't let me have it. I do well at school, sometimes I get the occasional B but all of my grades are A's. My average mark in science is 100! I gave them a list of 11 reasons why I should have a phone and they still won't give me one. I even told them that I would pay for my own phone plan but they won't give it to me. I asked them why and my mom said that I wasn't mature enough. What??? I dont want to brag but I'm pretty sure that I'm more mature than the 12 year olds who have a phone. And my dad just says I don't need one. Can somebody please help? They dot even need to buy a phone cuz they already have one! I just don't get it