#the tales of ba sing se
Zuko telling Jin that he and Iroh were in a traveling circus seems like a one-off joke at first, but now that I think about it, we do hear about traveling circuses specifically in the Fire Nation and its territories. Specifically, we hear about Ty Lee joining the circus, which is an easy frame of reference Zuko might have.
The other time we hear about circuses is also of Fire Nation origin, in “The Deserter.” Most of the information I found on this comes from the wiki, which says that the Fire Days Festival that Aang and co. attend is a traveling show that includes firebenders that is meant to bring Fire Nation culture to Fire Nation occupied towns in the Earth Kingdom. So, this could be a conceivable reason why a pair of Fire Nation citizens who are firebenders might be traveling in the Earth Kingdom. So, really, if Jin thinks Zuko is a juggler and guesses that he is a firebender, she might be able to come to that conclusion as well (despite Zuko’s terrible juggling.)
Zuko also might have come up with that alibi because it was something he had an interest in, given how he also recalls other examples of Fire Nation arts, like going to the theater as a child, and the blue spirit mask having special significance for him.
It’s also the typical fantasy of an unhappy child, and since he actually knew a kid who joined the circus because of not wanting to be compared to her siblings, this might have actually been something of a secret fantasy, a life he could have had if he were someone different.
