I wanted to echo the last poster. I don't think you should worry so much about your baby decision. I was pregnant, while morbidly obese and it was not fun. My back killed and went out, I had gestational diabetes, hypertension, and ended up having a c-section. 8 week after the delivery my back went out again.
I believe if I had less weight on me my pregnancy would have been smoother.
I see no reason why you can't wait. Take care of yourself, right now, you come first. Then, when you are healthy, you can take care of your family. :-)