Nursery nursing: love babies, hate answering call lights, prefer peds to adult nursing, prefers nursing patients who can't talk back to you, like pt education as many moms need lots of help. Idea of a "bad day": only getting lunch break & "pee" breaks. More of a continuous flow, steady, predictable job: morning rounds then feedings then afternoon rounds, then feedings w/ some admissions & discharges thrown in.
L&D nursing: love adult patients, enjoys taking care of so-called "challenging" patients, as most moms are not at their best, loves pts families/visitors 'cuz everyone knows what is best for THEIR daughter/sister/etc., love long hard days where your skills & your professional attitude make a big difference, being an "adrenaline-junkie" helps, as you never really know what will happen next on the unit, ability to think fast on your feet, able to work well with sometimes-challenging MDs.
re: can a person know her specialty b/4 graduating? absolutely!
Three of my former L&D patients have now become L&D RNs on my unit! They are the greatest compliment I have ever received, as they chose their careers based on care they received from me.
Maybe ask the unit manager in a busy OB unit if you could do some volunteer work or maybe get permission to do some observations.