How to bring up asking my mom if i can buy GTA 4?

I'm 13 years old and i really want GTA 4. my dad says he thinks im mature enough and hell think about it but i need to ask my mom as well. the only problem is that my mom is more of a stickler about videogame content than my dad is and i can't figure out how to bring up the question or to convince her that I'm mature ebough like i did for my dad. please help.