In my opinion the best way to know if you will be a good fit for neonatal nursing is to try it out. And by that I mean try to shadow a neonatal nurse in some way. If you can't, then there is no other choice than to try it out firsthand. In nursing school I was able to do clinicals in long term care. I asked my instructor if one knows if they are "cut out" for a certain specialty like long term care and she said yes. It was then that I knew I wasn't cur out for long term care. Every aspect of nursing has its pros and cons and some cons are harder to accept than others. Remember, your training will help you and ask for help whenever you are struggling.
Best of luck to you!