I disagree with industry standards
Which you certainly have the right to do. But if agents and editors agree with them, don't you have a bit of a problem?
so take my response not as a suggestion but rather as a personal opinion. In my opinion, they're holding onto old standards even though kids this age are trending in the opposite direction.
Actually, no. What you've done is lump all MG and all kids into one group, as though kids are kids and books are books.
This tells me that Insert "some" here and this statement becomes truekids this age want longer, more developed stories. They just don't want thin little books anymore.
Which "they?" I can give you the names of a whole bunch of kids who won't read anything over 100 pages unless it's Diary of a Wimpy Kid.
Mine's at 184 pages What's your word count? 184 @ 250 words per page = 46,000 words. Unless you're writing for early MG, your word count would be fine. Most agents would look at it, unless they felt your premise was better suited to a younger audience that isn't ready for that long a book.and I was told to chop it.By whom? Consider the source and the reasoning behind the suggestion. I prefer to chop for improvement, not chop for the sake of chopping.
Are you sure you wouldn't be accomplishing both? Trimming sometimes improves pacing quite a bit.
The Crowfield Curse: 319 pages.
reading level 5.8 62K words
The Slippery Map: 288 pages.
reading level 4.5 52K
The Calder Game: 375 pages.
reading level 5.8 53K
The Lightning Thief: also 375 pages.
reading level 4.7 87K, established author
Sir Fartsalot Hunts the Booger: 214 pages.
reading level 5.2 29K
Fablehaven: 351 pages.
reading level 4.8 75K
No Passengers Beyond This Point: 241 pages.
reading level 3.9 50K
Here Be Monsters!: 528 pages.
reading level 4.9 71K
These are all books popular with fluent readers. Kids who enjoy diving into a story. Only Lightning Thief goes beyond 75K. For MG fantasy, you'll have no problem getting agents to look at your work if you're in this range. I've heard agents say they won't look at MG under 30K. So if you're between 30K and 75K, you won't be rejected solely because of your word count.
I've got two Joe Sherlocks and two Encyclopedia Browns over there that come in well within limits.
Those are considered early MG or even chapter books. They are intended for kids who don't yet have the skills or interest to read longer books. If that's the audience you're aiming for, then yes. You need to stay under about 25K.