Realizing that trying to explain the truth would just sound like a little girl playing make believe, you take a moment to think of a lie that will get you a chance to go back for a different uniform.
"My brother is here to get a JROTC uniform. I was supposed to stay by the changing rooms, but I got lost looking for the bathroom."
The man nods, "Alright, what's your brother's name?"
"Uh...Jack."
"Do you know your last name?"
You shake your head.
He leads you over to a chair and says, "Wait right here. I'll go look for Jack."
A moment later he's gone and no one seems to be looking your way. Now you just need to sneak back into the uniform room and try not to make a mess this time. Except it looks like your claim of needing to use the bathroom wasn't a lie, as you feel a sudden urgent feeling emerge.