Hey Kerra,
Have you tried telling them why it is you want the cat? Also you could try explaining that you'll take care of it and prove that your responsible.
Also it may have to do with the age of the cat. Kittens are cute and adorable but their a lot of work, I have a kitten and I love him to death but he's a handfull. He's very very playful and needs lots of attention and he has very sharp little teeth. You also have to train them to use the litter box.
If you get an adult cat its not as hard. They tend to be a bit more relaxed and if they aleardy know how to use the litter box then it shouldnt be to hard to get them to know where the new one is.
Goodluck and I hope your parents let you get one
