NEED ANSWERS URGENTLY ! X?

Hi there. I am 15 years old and all my life i have wanted to ride a motor bike. My dad knew roughly about this when i was like 7 but he kept quiet. But now he wants to sell his motor bike and i said i want to have it and he said no way am i allowing you the roads aren't safe anymore. But isn't it my gamble ? I also have been having thoughts of joining the army but if he wont let me ride a bike what the hell do you think he will say about the army ? Im a real dare devil and i have always lived life to the full ! He wants me to be a doctor or something but i am really bad at maths ! Please any advcie abotu what i should doooo ! ??? Thanks, x