Well the good thing in NICU is that you can usually see your patient's veins, so finding them isn't the problem. The problem is that the veins are very tiny, barely bigger than your IV catheter (we use 24 gauge), so it is much harder to thread them in. We also do arterial punctures for some labs, and once you get a blood return, you really can't move a muscle until you get all the blood you need. Those vessels are so tiny that the smallest movement can knock you right out. The babies are moving, too, so you've got to keep them still at the same time as keeping yourself from moving.
However, not every NICU nurse is good at IVs or arterial sticks. I know that I suck at IVs most days but can get almost every art stick I try. There are other nurses who are great IV sticks but can't hit an artery for anything. It all balances out. You'll see!
The newer incubators coming out raise and lower so that you don't have to bend. The old ones are made for people that are 5' tall - I'm a little smaller than that so they're perfect for me, no bending! It's much less physically exhausting than med-surg, I can tell you that. I was a CNA in med-surg during nursing school and it was heck. NICU is very very easy on your body compared to most specialties.
We're also less busy than most floors, for the most part. Having 1-4 babies to care for, usually all within 50 feet of each other...even on your busiest day, it's still better than running up and down an entire med-surg floor all day!
Just apply for the NICU. An ICU class really won't really help you because adult ICU is so much different than NICU. I mean, take it if you want because maybe you might end up in adult ICU at some point if you decided against NICU. But overall, they're going to teach you everything you need to know about NICU during your orientation. We don't take an ICU class, we take Neonatal Ressucitation instead, and your hospital will set that up for you. Just make sure that the hospital has a good orientation program for new NICU nurses - because really, you're going to be like a new grad. Of course you're going to be better at time management and have more confidence because you are an experienced nurse - but as far as patient care and everything that we deal with in the NICU - it's all new.
Good luck, and welcome!!!