Really Want A Dog But My Parents Wont Let Me?

I have been wanting a dog for several months now. I have had 2 dogs in the past but my dad got rid of them. One of them had brain damage and the other we couldnt potty train. But that was about 2 years ago. They were our first dogs so we had no idea how to potty train them so… bye bye! But i have been on Petfinder.com and have watched all the dog traing and care videos. i watched them all so much, i practically memorized them! i really want a small dog like a bichon friese or cockapoo. sumthing like that. i have good grades and am very responsible. i have a 3 year old tiger cat who i feed, excersise, and clean the litter box for. ive had him for 2 1\2 years. i have researched dogs and breeds and i know im ready? but how do i persuade my mom and dad? ive tried EVERYTHING!!!
~Amy

I Have A 3 Month Old Cockapoo Puppy That Is Pad Trained, I Want To Start To Train Him To Go Outstide, But The ?

last puppy I had was not trained to the pad so I started training him to go outside, but he was 6months old until he really understood, should I wait until this puppy is 6months old to start outside training. Also my dog will pee on pad but will not poop on pad is there something i can do about this.