I taught my daughter to read when she was 3. At that time she loved being told or read stories and she got a lot of them. Because a lot of her stories didn't come out of books, she didn't necessarily care that much about the medium. I think that may be the secret. I also taught her to type (on a computer) before she learned to write. By 5 she was a very fluent reader. She is now 35, so that was a long time ago.
I can't see any reason why children ought to be put off ebooks, other than an addiction to pictures. And one way of getting round that is to say, "Shall we draw a picture of...?"