I totally understand how you are feeling. I am young and have been married for 3 years now. I don't get too much pressure from our families because they know better, but we do get it from other people. People automatically assume we are going to have children, and are bewildered when I tell them we are not sure whether or not we will have kids.
I think there are two type of people in this world, the ones that have that yearning in their loins to spread their genes, and the ones that don't. I happen not to have that yearning, but it doesn't mean that I won't eventually have kid(s). Who knows? I don't think its anyone elses business