How do i convince my parents to let me get a drivers license?

-so im 17, 4 more months ill be 18, and i dont have my drivers license yet. My mom dont much like being in a car with other people driving and thats ok. As for my dad? I dont know. He let my older sister and brother drive all the time and even bought them new cars. And my brother has been in jail 2 times befor that. As for me, i keep straight a`s. Never get into trouble. And work at McDonolds after school and during the summer. So how can i convince them to let me get a drivers license? They wouldnt let me take drivers ed in school in the past and this is the last chance i got cause im a senior in HS... SO PLEASE HELP!!Just ask them if it's okay to get your drivers license and promise that you won't do anything stupid like drink and drive. I don't think they'll deny because your siblings got their license before you. If your parents are the type that are afraid that you're growing up too fast, then ask your siblings to take to the DMV.