Please see below re: reasons we should get me a cat.

1. Most Hogwarts students have a pet of some sort, and I will be a Hogwarts student in the autumn.
1a. Toads are quite disgusting.
1b. Owls, while the practical decision, are readily provided by the school itself. It would be foolish to purchase something with a finite lifespan when the school already makes them available. An owl would be a much better gift for the conclusion of my schooling than the commencement of it.

2. I am very attached to family. While I shall never ever say so out loud, I shall miss my family when I go to Hogwarts. A cat will soften the blow.

3. Cats largely take care of themselves, and so are a logical first pet for any child.

4. Even with that in mind, a pet of any sort is still a responsibility. At my age, it is high time I learn to be responsible. Think of it as a stepping stone to being able to run my own house in six short years. Through that lens, it's rather a necessary stepping stone.

5. They're really cute

Sincerely,