That is so wonderful. I haven't found that one great librarian. Keep her close. I have made great use of the library's mobile app. It is the only way I can manage all the requesting, looking up of books, and keeping them all renewed. (We have about 75 books checked out right now.)
It is interesting what your librarian has observed. I have only seen it happen once with my own DD, but it was exactly as she described. DD was reading obsessed from about 8 months on. When she was a toddler we would read for an hour at a time multiple times a day. I always had a stack of books ready to go next to my chair. We started chapter books because of the practicality of it.
Now she reads to herself for at least an hour a day. She will easily read a magic treehouse or rainbow magic book in one sitting. At the library, while I am looking for books, she will choose and read story books for 30 minutes. She reads in the car. She reads before I wake up. I think it might be more unusual for her to be reading this much at this reading level than her actual reading level at this age.
Something I have noticed is that her comprehension and vocabulary exceed her decoding skill by itself. I think comprehension has always been the driving force in her reading development. She really has had zero reading instruction other than learning letter sounds and reading with us. But, we read a lot. Even, now, at four when free time is more scarce, we read to her at least 45 minutes a day at bedtime.
So, keep that love of reading going. A literacy professional/acquaintance once witnessed DD reading and commented on her "brilliant" pacing and ability to slightly modify her voice when reading dialogue. You can't teach that with flashcards and videos. Decoding will come. It is that passion for reading that needs to endure.
