I had a lot of classmates wet themselves in fear of doing presentations. It wasn't embarrassing on my part, but it sure was funny.

I can't think of any experiences I've had personally though. You'll be fine though

EDIT: Wait, I've got one. It was cold one day in year 3 so I wore tracksuit pants over my school shorts. They were black. And I wore the school jumper. It was blue. I clashed horribly and looked like a marshmallow.

Also I was routinely called a girl for having long hair. I mean, it was midway down my back. Those days sucked though