Understanding science

So after much more research, it seems that the first 6 years are just nature studies and science does not step in until grade 7.  How and when does things like the human body (introductory for elementary) happen? While being outside is never an issue for us, how and when do you fit in other things.  I love the living books, but am beginnign to wonder if it is too much, especially for an active boy where hands on might be better.  Yes, I have been all over Pinterest looking at various experiments, etc and hope to share these, but how do you fit it all in, or do you?  I want to do introductory astronomy, too.  A little overwhelmed tryign to figure this all out.  thanks