Chloe's cousin plot hole.
In S1 E20, when Chloe leaves for her interview in Metropolis, she mentions she's staying in her cousins dorm, implying her cousin is in college.
Later, in season 3 I think, we find out Chloe's cousin is Lois Lane but when Lois is introduced in season 4, she is only around a year older than Chloe, who was a freshman in highschool when she went up to Metropolis and supposedly stayed in her cousins dorm.
Yeah you could easily say it's a different cousin but no extended family besides Lois is ever mentioned again as far as I know.
Before you get mad at me, I'm not saying this is something that makes the show worse by any means. I'm just on a rewatch and I've been having some fun picking up on little plot holes. I don't expect the writing in a 10 season show to be flawless, especially not one made in the early 2000s without initially having the rights to all the characters.