I am a NICU nurse AND an SRNA heading into my senior year. A lot of schools don't take NICU experience but some do. My class has 9 pediatric nurses and 5 of them have only NICU experience. Everyone in my class is doing extremely well. I have found that the transition to adults was easy for me and some of my classmates took a little longer to adapt but you can definitely cut it in anesthesia school. I did work in a level 3 NICU and was a travel nurse for 5 years before school and I think that definitely helped. Bottom line is some people can cut it and some can't. Adult experience is good but isn't absolutely necessary. Whatever you think you know about nursing, no one knows anything about anesthesia starting school and the playing field is pretty level at that point so if you find a school that allows you to go with NICU experience dont worry about Adult ICU experience, you'll be fine :)