Is The Hobbit too advanced for 6yo at 3-5th grade reading level?

It's Christmas time. My oldest niece has reached a very high reading level this year for her age and I want to make the plunge and get her The Hobbit. But the last thing I want is to give it to her too early and she finds it daunting and boring. She does like fantasy, I've given her smaller fantasy books in the past and she's read them a few times over. Her mother (my sister) said they are buying her books for 9-12 year olds.

I couldn't read well at all growing up, still struggle at 33, and first heard LOTR as a child because my uncle read it to me this time of year before we got the movies. I want to pass on the tradition, however I live far away from them. TIA!