The Pre-teen Girls are a trio of pre-teen girls who are regulars at the mall. They're usually seen hanging out with each other or with other pre-teen kids. They're also known for being fangirlish about many things, such as with Wyatt in "Idol Time at the Mall", Jen in "The One with the Cold Sore", and Nikki in "Fashion Victims". The tall one with the braces has two color swaps (meaning she has been seen in two different sets of clothing).
Their largest appearances have been as fans of various members of the gang when for fleeting moments they are famous. This is true of Wyatt in "Idol Time at the Mall", as he was briefly famous on the strength of his reworked song about his friends. The girls in that episode were fangirlish about him and, due to his song, hated his friends. They behaved much the same Jen becomes semi-famous in "The One with the Cold Sore". There, she was more famous than Wyatt was in his episode, as she was one of the supporting characters in a film set in the mall. Although it was not announced to the general population, everybody in the mall heard about this, and as such became Jen's fanbase. This was not left entirely to the girls, as the whole mall loved Jen, but they were some of her more vocal supporters. The three fangirled about Nikki in "Fashion Victims" because Jonesy had made T-shirts and split them into teams; Team Jonesy and Team Nikki. The Nikki shirts sold well, and as such Nikki garnered many unwanted fans, including the aforementioned girls.
Strangely enough, they don't appear at the end of "The Journal". This is odd, because Jen is widely revered at that point in the episode, and the Penalty Box Customer even tells her that he's naming his six-year-old child after her. As such, it would be a perfect time for them to appear and go gaga over her, but this never happens.