Having been a father for six months or so, it's clear to me that nobody can truly be prepared for their first foray into parenthood. That's the first point everybody seems eager to impress upon you. No matter how much you prepare yourself, you will be unprepared. However, I do think one can still be ready to be a parent. Which is to say, while we must admit that we don't know everything, we can educate ourselves and, more importantly, be ready to start the arduous task of trial and (without question) error that is raising a child.
I think the most important part of the education available through the hospital, OBGYN and/or pediatrician is that it gives parents a starting point. You will still have to learn some lessons the hard way, like always, always putting a clean dity under the dirty one before you open that bad boy up. But at least you'll know what a dity is and how to put one on your bepooped lil' baby. And while nobody can ever prepare you for the sight of a perfectly shaped, intact meconium bubble sprouting out of that tiny butt (true story), at least you won't try to return her to the baby store for a refund.
In other words, knowing that you will never have all of the answers should not stop you from finding as many answers as you can. Knowledge certainly is power and in this case you will not only be at least partially prepared to care for a kid, but it'll give you something to do when you're not trying to convince your wife that Rutheford Optimus Flex Von Hossenpfeffer is a good name for a boy.