Congrat man.
a little about myself. I was 19 and she was 17, high school sweetheart. we dated for 2 years and she got pregnant by accident. I decided to marry her and had our first son at 21. it was a real challenge because I just completed college and she just completed high school. we were not ready financially, mentally, etc....So i ended up going to work, go home help her with the kid, she went to university after spending a year with the boy. we had to rely on my lowly income for 5 years and I had to pay her tution, etc. but we made it out in one piece and we just had our daughter last year at 27. Now i'm 28 and I have a 7 years old boy and 1 year old daughter. my wife had a bachelor degree in nursing and now we are working full force to pay the mortgage. I took the rough road, i know.
look back on my situation, i think you will be just fine since you both are at the right age and financially stable. remember to be very patience and love your kids as much as you can because they are the cutest when they are young and you will never get that back again once they pass that age. I still regret to this day that i didn't spend more time/pay more attention to my son when he was a little baby. now i'm more ready with my daughter and I just wish that I can turn back time so I can do thing that I'm doing with my daughter right now. love your wife unconditionally because she will go through lot of emotion after the baby especially the first one, she can be mad, crying, going a little crazy. just try encourage and be there for her. help your wife take care of the baby as much as you can especially the first 3 months where she is not fully recovered. so it is not really good for her to walk around too much or do heavy task. you will need to handle most of the tasks that she used to do before in the house.
enjoy and remember to take lot of pic/video as much as you can. this is the best moment and later in life you will love it when you look back at pic/video of your kids.