I am a first time dad with a 4 month old. All the dads here on the forum are dishing out fantastic advice. I found that the most frightening/nervous thing was taking my daughter out of the hospital and bringing her home. Thats when the weight of it all hits you. No more nurses or doctors to take care of something you think is wrong, or may be wrong.
You treat your baby like a Faberge Egg for those first few days. Every 3 hours they wake up and want to eat. That lasts for the first few months. So ya, only the dads here know what true sleep depravation is. Changing diapers at first is like doing surgury, after a while it becomes second nature and you get really, really good and fast at doing it.
In general it hasnt really changed my life that much. At first I thought everything would change, but I still go out with the boys for beers once or twice a week. We still have people over for dinner and still get invited to friends houses for dinner too. Just try to relax and deal with everything day to day. Its ALL worth it the first time they smile at you !!!