Is there any true mental disorder behind wanting to be a teenage mother?

Before you jump to it, I AM NOT TRYING TO GET PREGNANT and I know how hard it is to have/raise a child. I'm only a teenager, but I have six younger siblings, have babysat for about three years (including long, long days, feeding, baths, changing, bed-time, nap-times) I know the cost of having a child and I work in a birthing center/have seen the pain women go through to have children. I know that I'm too young, and not mature enough, and can't support a child in any way, but I know for a fact there is this stupid part of me that's dying to have a child to love and care for. Someone that looks up to me and that I can coddle almost no matter what. My parents are good parents, but I want to be different, and I also can't stand people telling me what to do. I think I'm trying to make myself believe having a child means I'll be making the rules and choosing how to raise him/her, but I just long for having a baby in my arms, and taking care of them 24 hours. But I know that I am NOT financially prepared, nor do I have a boyfriend,and about two friends that would hardly support me while having a child. Is this some type of mental disorder or is it normal? I find myself getting upset for wanting a child, and I also have this urge to become a single mother even. I'm a fiction writer, so I have that big imagination, but I truly don't like being miserable because some part of me is dying to be a mother. And please don't advise me to find out how hard it really is to be a mother-- I've taken care of my siblings over night, cleaned up puke, washed the crayon off of the wall, and have listened to the 3-hour screaming all night before. I know it costs a lot, and I know it'll wear me out, I've told myself this a million times, but I can't get rid of the feeling. I've had repeated dreams of being a mother and being SO happy that somebody finally acts like they want me, and I have someone to love. I just hate being miserable :P Also, people have said I act very mature for my age (which I kind of have to with having so many younger siblings and responsibilities around the house) Can anyone help?