Im not even pregnant yet..

I'm not even pregnant yet and I am already very stressed out about how I want to raise my child. We babysit my spouse's nephews a lot and whenever we have them over for a weekend I'd feel very stressed out thinking 'this is not the life I want!!!!' And I would be having sleepless nights getting stressed out how to raise my own kids... Question for mothers.. How do you know if you are ready? How do you prepare yourself to them 'properly'?