Today, DS1 asked me when his first day of school would be. I think he may have been thinking about his cousin who started kindergarten a few weeks ago. I told him it was a long time off and talked about how now that he doesn't go to daycare because Mommy is at home, that we might have school at home also. He really threw me off guard. A little while later I asked him if he would like to have a "first day of school" soon, and he answered, "no."
I have a lot of books from Sonlight's Pre-K program, and some Math U See stuff, too. But we don't "do preschool". The closest thing we have to structure is our weekly playgroup dates.