If you're living on your own and supporting and taking care of yourself then there is no reason you shouldn't be able to take care of a dog. Get one anyway. It's your life and if you can't take care of him then you can give him to someone else and find him a new home. You will never know until you try. If your parents are nervous and overprotective then you are going to have to eventually do something they consider disobedient so it might as well be this. They will get over it. They may worry more for a bit but they will get over it. And you will also get over any guilt you feel about it. That's normal feel if they have controlled you your whole life, but it's something you have to go through if you ever want to be emotionally independent.
I have four grown kids. 27, 22, 21, and my youngest will be 20 next month. My 22 year old is moving out next month and it's very sad for me because I know that unlike my boys, she won't be moving back home every so often. We talked about feelings and she said that even though we both know this is a good thing for her and the right thing to do, she feels guilty because I will be sad for a bit. I told her that's normal and will pass. So this is similar for you. Your whole life you tried to obey them and not make them worry or be mad and now you are doing something against what they want. But you are an adult and you need to do what makes you happy, not just what makes your parents happy.
Get the dog, tell them you are getting one and that its not a subject t you care to discuss with them because the decision has been made. Tell them you appreciate their concern but it's not open for discussion and if you have any problems with him that you will handle them yourself and not expect them to solve them for you.
What kind of dog do you want? I have two high content wolf husky hybrids and one purebred husky. They are pretty high maintenance so I wouldn't suggest that kind for an apartment. Labs are good dogs and as long as you take them out for daily walks and spend time with them they are good companions. So are golden retrievers and German shepherds. I don't know much about small dogs because I hate small dogs and haven't spent much time around any that changed that opinion, so I can't suggest a small breed.
If you want something lower maintenance than a dog though, you could just get a car. Cats don't need much of anything except litter and food. They come to you when they want to be petted and they don't require walking and they aren't loud.
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I'm giving it another shot. We will see.
My forum is still there and everyone is welcome to come join as well. There is a private women only subforum there if anyone is interested. Also, there is no CAPTCHA.
The link to the forum is
http://www.rightplanet.proboards.com