My daughter got a phone last year when she was twelve. I originally decided to allow her to get a phone based on how well she did in school, did she do her chores everyday and did she show responsibility.
She got the phone on the condition that she kept all of those up and was responsible with the phone. She had to show me that she would take care of it (not dropping, losing etc.) and that she would use the minutes responsibily. I told her if she abused the minutes it would be taken away.
A phone was very important to her so she lived up to all my expectations. The minutes part wasnt very hard since she mainly uses text messages.
So, if I were you I would show your parents that you are responsible.