I don't remember the first book I read. I was probably 5 or so. But my grandmother got me the C.S. Lewis Narnia books when she was in England and I still have them. They were paperbacks and have become very delicate. So I have a second set for re-reading.
I was a voracious reader as a child. We lived on Library Street growing up and the library in our small town was open on Weds and Sat. You could take out 7 books at a time. It wasn't enough!
I probably have in excess of 5000 books in this house now. When I move things into the addition, there's probably going to be a lot of weeding out.