I strongly recommend the book The Nurture Assumption by Judith Harris. It has done more to shape my mindset about being a parent than anything else I have read. You could also wait a few years to read it, as it is more relevant once your child is old enough to start having social interactions outside the home.

Honestly, the changes in my marriage were much more difficult to handle than actually being a parent. You and your spouse (assuming you are married) will change as individuals once you become parents, and issues that never came up before may suddenly feel like relationship deal-breakers. I have no advice to offer because frankly I didn’t handle it well—just a word of caution.