Agreed. I'm opposed to the notion that when children read a book, it somehow disrespects the book. Children are people just like anyone else; if they can't handle something, they can't handle something, but otherwise, nothing bad happens to the book.
I recommend the Lionboy trilogy by Zizou Corder. I would hardly call them "fantasy," though--they're sort of a weird hybrid between fantasy, "realistic" adventure, and science fiction. The main fantastical element is that the main character can talk to cats and other members of the Felidae...
There are some forums here labelled as "private" that only people with at least 5 posts can see. Well, I have more than 5 posts and I still can't view these forums. Why not?
Sorry if this isn't the right place to post this.
Eragon was what got me into fantasy in the first place. I definitely think the series is underrated. Not the best series in the world, and certainly not very original, but all four books are enjoyable reads, and the ending is not as predictable as some would have you believe.
I would listen to the mom side of you, then. If you explain it in a way that makes sense, then the reader will learn about science, which is always good, and if you make it interesting/entertaining, then they'll keep reading your story.
Not that I'm an experienced writer; these are just...