I don't want people to know..

Anytime someone in my family makes a comment about me and my fiance having a kid I act like I don't want one right now and like I want to wait. Honestly we've been trying for almost 2 years. Nobody knows except my best friend. Is that wrong?? I just don't want the lectures about us being "too young" (we're 20), or not being ready yet.. I want a baby so bad and I think we are ready and we can handle it.