When I buy new books for my kids, I don't put expectations on them for how or when they need to read them (unless, of course, they are explicitly for school). I just hand them over. I did exactly that when these books arrived in the mail. I handed the package back to Mary-Catherine (we get the mail on our way out to do errands) and told her that something had arrived for her. The minute we got home that night, she changed into her pajamas and began reading the books. She made sure to get her own Peter Rabbit so she could read to him! (Technically, I'm pretty sure he's the White Rabbit from Alice in Wonderland, but she has called him Peter Rabbit ever since she first got him!)
She has probably read these book just about every day since we got them. I know for a fact that they haven't left the desk next to her bed. Further, when she realized that there were more books, she immediately put in a request!