How soon can I start reading to my son. My son is two and I can’t wait getting started!

Katy, I think you can start right away. Our daughter picks the books and we read them together. She is only 2 years, so the books have a lot of images and very little text on each page, but there is still a lot to talk about and learn as you go through. Read to her, I think is also fine. Don't be frustrated if your little one is distracted.