How do you persuade your parents into getting a facebook?

i am 13 and i did have a fb but my dad disabled it because i wasnt allowed on because i was grounded and they caught me on my ipod because i was on chat by accident and that was back in january and i asked my dad i i could have it again and he said i was acting like a moron on it and i was mature and stuff so now i asked my mom and told her i wont say anything "ghetto" like and i will takr good pics. shes now fine with it and shes gonna ask my dad tonight but im scared he'll say no. i hope i persuaded my mom good enough to persuade him. im like the only girl in the school who doesnt have one. except for 6 others but i need one again! help me to persuade better! thanks:)