What would you suggest if I knew I wanted to be a nurse working with babies and toddlers but I'm unsure what specifically I want to pursue?

Since you already know you want to work with babies and toddlers, start in Pediatrics in the hospital to gain and solidify skills and judgement for a couple of years. Then move to pediatric ICU, NICU, outpatient clinic, visiting nurse specifically for pediatrics, or even labor and delivery. The time spent on a pediatric unit will allow you to explore "next" options by learning from your colleagues who likely will have been in some of the positions I've mentioned. Go to pediatric nursing conferences and network with other nurses about where they work and what their jobs are like. If you find you enjoy older children in the process, there's also school nursing to consider.