Lots of changes for your family then. Hopefully all good ones and won't cause too many upsets.
I trained as a nursery nurse many moons ago and my first job after I qualified was in a hospital nursery. I loved it and after a couple of extra courses were under my belt, was in charge of the 'baby room' as it was called then. I had one other full timer and two students, sometimes three, with up to twelve under 1s most of the time. After a couple of years, the then Matron (head of the whole nursery) went off on long term sick leave and I was made Acting Matron (how to make you feel old, at the time I was only 24, younger than several of the other members of staff). Talk about in at the deep end, with all the paperwork and staffing issues, I spent more time in the Office than with 'my' babies, so to begin with I didn't like that, or having to tell the other staff, most of whom had been there longer than me but were, on paper, less qualified, what to do.
In the end, I settled to it, changed quite a few routines to make things a lot easier, managed to get our budget increased quite substantially and when the previous Matron decided not to return to the job, the position was mine permanently. I only left when I became pregnant with my first daughter and the travelling and shift hours really weren't compatible. So, I get where you're coming from, even though I'm sure these days, with Ofsted etc and regulations a lot tighter, it is quite different.
From what you've said previously, and how you came to be given the role, I reckon you'll soon settle into it too and feel more confident. Its just that for all of us, changes make us wary and looking for problems before we even know quite what to expect. I really hope the current staff work alongside you to make those changes less daunting and you'll soon be running a very happy and well run ship