So, I remember being read a book in elementary school (so it was at least written by 97-98). It was about a girl in the 1700-1800's who found out she was actually part of an exhibit in a history museum - The entire younger generation thought they were actually in the time period, while all the adults were in on it. Could someone help me identify this story?
I believe you're looking for Running Out of Time, by Margaret Peterson Haddix (1996). From Wikipedia:
Jessie Keyser is a 13-year-old girl from the village of Clifton, Indiana, in the 1840s. During a village-wide outbreak of diphtheria, Jessie's mother reveals it is actually 1996, and Clifton Village is a tourist attraction, a replica of a historical village. Her mother asks her to retrieve a cure for now her own sister Katie has taken ill; the owners of the attraction ceased to provide modern medical care to the villagers in order to preserve its authenticity. She tells Jessie to get the cure from a man named Isaac Neeley, who did not think Clifton should be a tourist attraction. Jessie's escape will be difficult, because Clifton is guarded to ensure that none of the villagers leaves or finds out it is actually 1996.