I'm currently writing a realism fantasy novel targeted for a 9-12 age group. Since it became so long(the first draft turned out to be at least 90,000 words), I figured it would be best to split the book up into a series. Now after finishing the first book of the series, it somehow managed to be 70,000-80,000 words. Doing a quick Google search, according to this, it claims that the average word count for Children's novels would be 50,000-70,000 words as the average.
There is going to be like, 5 sequels to the first book, so the first book is just the beginning. This is the type of those books when there is a long journey. For most of the series, it's basically the character journeying around and running into many mini conflicts. So while yes, I could easily just cut off a part of the story and carry it to the second book and so on, this is going to be a bit difficult to do, because the ending of the first book is a cliffhanger, and I kind of like it that way.
Is my story too long for a Children's novel(targeted to that specific age range)? What can I do to make it shorter(perhaps I did too much fancy language or the show-not-tell?)?
Edit: I got my little sister to read the book. She's only seven, but she gobbled the whole book in one day. She said it was good, so I think that if she read it so quickly, then kids over than her would most likely too. However, she did skip over a few pages that were about my main character writing her diary entries.