Jenn Langston is a level 5 human that patrols Old Town within Stormwind City.
Other members of the Langston family include David, Elly, and Reese. They run Pig and Whistle Tavern.
See List of Stormwind NPCs.
It is unknown whether or not Jenn and the rest of the Langstons in Stormwind City are related to Karramyn Langston, the protége to Aedelas Blackmoore in Lord of the Clans.
In the original beta, if you slapped her she would chase you around. Now if you type /rude, she will just be rude to you.