Based on her dorky and conservative clothing, she's presumably one of the 'brains'. She's got more of a social standing than Daria though, and seems particularly popular with boys: she's seen walking hand-in-hand with Josh during the Bridal Expo in "I Don't", apparently goes on a date with Adam ("I Loathe a Parade") and chats with "Tiger Guy" in "Fat Like Me". The aforementioned date was at the school homecoming parade, which she seemed to enjoy.
Jenna in fanfiction
She's rarely appeared in fanfiction. One of her first known appearances was in Trapped by Jim North, where she appears mostly as a spider-infested corpse. It is significant however for giving her a fanon surname of "Schwartz".