Im 16 1/2 and i would like help convincing my mom to let me get a tatoo?

im in the fire department and want to get the insignia tattooed on my right shoulder blade. its Ghana take some time but i need some help trying to get her to say yes. my dad said get some thing that has meaning. when my mom asked why i want the insignia i said at lest im not asking for a skull or a naked chick. so any suggestions?