He gets mistaken for a girl on a school camp I think and put in their room?
Don't know if this helps or is the right one.
There is one call "The Wrong Camp" but the boy is
name Pat.
https://storiesonline.net/s/50809/the-wrong-camp
https://storiesonline.net/a/justthisguy
Story: https://storiesonline.net/s/11052/odd-man-in-college
Author: https://storiesonline.net/a/Ernest_Bywater
Dr Grey arrives to find Lyn sitting at the table while giggling, she asks, "OK, Lyn, what's the problem now?" Emphasising the last word.
He looks up, "Ah, Doctor Grey. This is Nancy, my bunkie. I've got the last dorm bed available on campus, and it's in the Leslie Building."
"What!" She grabs the paperwork, and goes through it. It does list Lyn as a male, but the attached photo has him looking very feminine. She slowly shakes her head, "If your bunkie has no issues with it, they can't. So take it, and be glad of the room and bed."
As much as I would like to enjoy Ernest's writing, most of it reads like a bad book report for a good book.
One of Ernest Bywater's Clan Amir books includes a similar event. The chapte Weekend Party in Falcon Chick
I can second this one. MC's name is Ruth and is misrepresented as female when set up with a foreign exchange student.
I think I will reread it now.