I'm never going to feel ready, for my trip, for marriage, for life. No matter how I prepare or lack of (cough), I'm never going to feel completely ready for the tasks or changes in life. Like a batter at home plate, the baseball is never going to be thrown at you in a straight line. It's going to curve, it may even have an unexpected spin. The thing is you're not just going pull back and let the chance at a home run stop you from swinging your best shot back.
Just for the record I'm not a baseball player, so my analogy is probably slightly flawed to a professional, but it was the best I could think of. : P