IME, in a state, non-faith primary school, there is a requirement to have an "act of worship" and for it to be predominantly Christian. This is open to a lot of interpretation, some schools are very secular and cover it minimally along with other religious education info in a matter-of-fact way.
Others, especially those with links to a church (yes, even though they are supposed to be non-faith schools! Grrr) will use it as an excuse for a bit of fire and brimstone, getting in clergy to do preachy assemblies etc.
It also means an individual class teacher, if they happen to be very religious, will be able to spout that in the classroom and it's seen as OK – even though it's extremely confusing IMO, to talk about matters of faith as if they are fact, alongside teaching stuff that is actually fact (like 2+2 or what dinosaurs were) , to small children who have problems gasping that distinction. (Well, I guess that's how religions continue - indoctrination while young.)
My DS was taught about the crucifixion story in gruesome detail, in year 1 aged 5. He was horrified and terribly upset for weeks. Imagine the content of that story had been in a computer game - no one would think it suitable for 5yos. Yet his class teacher was free to do that, and teach it as fact. In a non-faith school.
So something like this may be going on at school, especially if she has a religious class teacher, and of course you may also get more of it at sunday school, depending on the type of church.
But as for what to do, she's very young and impressionable, and that will change. I'd stand back and say "yes that's nice love" a lot and act as if it's not a big deal. I'd only out my view if challenged, for example if my child told me I had to believe in god, I'd explain clearly why I don't. I'd be ready to answer any questions with calm, factual responses. "Some people think that, but most people don't." (Christians are less than 1/3 of the global population IIRC) "No one can really know if that's true, as it hasn't been proved." Etc.
I imagine she will grow out of it, and even if she never does, and becomes a bishop, that is her choice.