These questions that you're asking are completely natural and also mean you're going to be great mums - you are showing your concern and love for your baby and obviously want to do your best by them.
When I was pregnant with Freddie, because I spent so long trying to get pregnant, and then had to actually stay pregnant (my ttc journey was a lot easier than some though for which I'm grateful), I was that happy to be pregnant that I didn't really consider what happened after, it felt like the most important thing had been achieved. So it was when he was born I had the oh god what have I done moment, especially after we came home and my oh went out for a couple of hours and left me on my own. I wept.
But after those few initial shock days, I got more in tune with it, natural instincts kick in. My oh took Freddie out for a walk to allow me to get some kip and after 20 minutes I was ringing him, crying, wanting him to bring Freddie back. You will adjust (hopefully better than I did because you're already having these questions now), and although lots of things with a newborn are hard and trial and error to work out what is best for your lo, you will get there. And even though that might mean your baby cries a little longer the first time you're working something out, they will cry less the next time, and the next. All they need to know is that you are there, holding and trying to soothe them, they know you care just from your voice and your touch. Remember they are trying to work you out too, I remember smiling through tears and taking deep breaths before I said anything when I was at the end of my tether, because if they learn that you are calm (even if you're not) then they will respond.
Freddie is 5 now, I do not regret a single day. You will all be great mums.