The great thing starting with a baby is you get to grow with them -- you don't have to be an expert right off the bat.
Gloria Wall (mother of four, spouse of Larry Wall) also has great advice that is worth repeating: You don't have to be an expert in children to be a parent -- you only have to be an expert in _your_ children.
Just after our son was born this was wonderfully summed up by a friend of mine as being like levelling up in a game. You start off with the absolute basics of keeping them fed and clean, and then just as you've got the hang of that something new is introduce. Before you know it you're at month 24, and seemingly without effort juggling food, drink, changes, entertainment, nap times, and telling them what they just said is probably not appropriate in front of granny.
Gloria Wall (mother of four, spouse of Larry Wall) also has great advice that is worth repeating: You don't have to be an expert in children to be a parent -- you only have to be an expert in _your_ children.