Congrats.
We've got a 12 week old girl. It's been the best thing ever.
Like you, we are in our early 30's, had our fun, were ready etc. You'll be fine. Get in there and give your missus lots of help at the start. I changed every nappy, did all the cleanups, pretty much everything besides the breastfeeding (lol) for the first couple weeks until I went back to work. Your missus will likely be anxious about breastfeeding (if you're choosing to do that) and she will appreciate not having other stuff to worry about early on.
The birth was a bit crazy; for me it was just the emotion of seeing my wife go through the pain and crying. Telling midwives "I can't do it, I can't do it, I've got no more", but then digging deep again every time for another push. I was just so proud. It was a rollercoaster of emotion. Again, just make sure you're there for her. Rub her back, have cool washers for her face/neck etc. Massage her lower back. Try things, some help, some don't, she'll let you know which lol.
Are you doing ante-natal classes? We liked them and they definitely helped us. Some people say they're crap (and for some people, they may be! Everyone's different), but we got a lot out of them, and met some people we still talk to and the missus is going to have lunch with during the week etc.. (great for support as well, "is your baby doing this?" etc.).
Everything after is pretty much what you expect. Sleep-deprivation for a few weeks until you all get into a rhythm/find your cycles that work. Lots of poo, lots of wee, lots of milk vomits. Honestly though, it's no big deal. To get all cliche, you'll love your little one so much all the messy stuff doesn't seem to have any effect.
12 weeks and our girl is growing well, putting on good weight, sleeps straight through the night and is giving me the biggest smiles all the time now, I just melt.
Great times coming mate, 'grats again and don't over think it, just enjoy the ride.
