I wouldn't worry just yet. You won't be taking critical babies until you've had a great deal of training, and feel comfortable handling convalescing babies. When you get to that point, you will need to look beyond the emotional part, and take care of the baby. Don't forget, it's a baby first, then a patient. You will be very busy, assessing, planning, treating--you will have a list of "tasks" a mile long, not to mention the charting. And, you have the family to support.
By the time you get to a really sick baby's bedside, you will have months of education behind you, and you will be ready. Take one day @ a time.
You could start studying now. Find out if there is a text the unit recommends, and look for it on Amazon