Sometimes it is a situation where the "Want to" doesn't match the physical "can do". My DD2 was like that. A book lover from the earliest opportunity and always would want to "do it herself" rather than have it done for her, even when her physical skills did not align with her mental ability. In her case, we found a significant delay in her visual processing skills. When she taught herself to read, she developed her own strategies, some adaptive, some maladaptive. We did not figure this out until she started school and was made to "conform" to skills that were expected at her reading level, such as using her finger to keep her place, moving her head instead of isolated eye movements, etc. When all of these strategies were taken, her reading level went from 3rd grade to <1st grade!!

I am not suggestiong that this is your dd's situation, but rather that you might keep it in the back of your mind as you watch her delight in books as she does.