I just begged and begged and my dad agreed finally, for my "birthday present", I could bring a kitty home. Now I have an Oliver, he's a precious little demon. I'm going to be an old cat lady...
When I tried to convince my mom to let me get a cat, she refused to let me have one. So I just went and got one anyway. I know she secretly liked her, lol. Maybe that'll work for you. Or you could do what my friend did and hide a cat in your bedroom.