I've been in clinical practice, and in and out of nursing education, over a couple decades now, and I think it's a really bad idea for new grads to start out in clinical situations where they're working alone, without other, more experienced, RNs around to ask questions of, check things out with, and observe. Wouldn't you be working basically alone as a school nurse? (Not many schools have more than one nurse per campus, do they?) If the answer to that is "yes," I would definitely advise against it.
Once you graduate and start working, you'll be amazed at how much you don't know and still need to learn. Please don't set yourself up to fail by starting out in a setting where you'll be more or less isolated from your best sources of advice, guidance, and mentoring, other nurses
Also, if you start out in a role like school nurse and stay there a while, you'll have a v. hard time later getting an acute clinical position if you decide you want (or need!) one. Once you have some solid, acute clinical experience and expertise, you can always
"branch out" into any other area you want, but the reverse isn't necessarily true. Starting out and spending time in a number of non-hospital type nursing roles can close a lot of doors for you later on. I would encourage you to seek out an acute, bedside, hospital-based position and stick with that for at least a year or so, and then move on to whatever you really want to pursue. If you're esp. interested in school nursing, it would make sense to get some solid experience in pediatrics (inpatient, I mean). You can never go wrong starting out with that kind of experience, even if it's not something you particularly want to do -- think of it as "paying dues," or completing your nursing education -- and it will set you up for success in a wide range of roles a little later on.
Welcome to allnurses, and best wishes for your career!