What if I buy myself a puppy?
Do you want a puppy because you're looking for a friend, or to learn responsibility, or if it's because you like the way puppies look?
I just want to learn to have better responsibility
I'm glad that you want to learn how to be more responsible, but please be aware that owning a pet shouldn't just be a spur of the moment decision. You need to talk to your parents if a dog is right for you, since it's very hard to take care of.
I already have it.
Well since you have the dog already, you need to make sure that you take care of it. It will need shots to keep it safe and a lot of walks and attention every single day, if you can handle that then I'm sure you will be a great dog owner.