In your position I'd likely be saying that you work in early childhood because you love children, and now that you have your own, you are devoting all that love to them and will return to nurturing other children when the time is right for your family.

You don't have to go into the specifics about not wanting to use x centre or not enough spots (although I will be honest and admit that when asked for the five hundredth time why we don't put dd in care so dh can have a day "off" I've used examples from working where I do to state people are screaming for places they NEED so their kids can go into care, and I don't want to take a space from them, so yes, I've used it!), you could even say you're enjoying being a sahm for now

I must admit I find it odd that there is an assumption pre schoolers will be in child care at some point. For some family dynamics it's simply not needed or wanted. I don't begrudge anyone using care (hell, I was raised in an FDC house - without people needing care we might have been a family with zero income at all!) I just find it perplexing that there is an assumption that it WILL happen. It's not a necessary step like primary school. It's an option for families that need (or want) to use it