How to convince my parents to let me get a dog?

Showing more responsibility would be to, do the dishes, do your homework, take out the trash and recycling when it's needed too, clean the floors and counters when they're dirty, keeping your room cleaned, mowing the grass and offering help to your parents all things that show responsibility. It's even better if you do these chores without your parents asking you to do it. To top it off to show responsibility for a dog, if you have neighbours that have dogs that need to be walked, ask if you could walk them free of charge, this would also include picking up the poop behind the dogs, i would have suggested to volunteer at a shelter but they usually hire only people ages 18and older for security reasons.