There was a student named Eliza Margaret Felder in the rolls of the Mordecai school. She attended from mid-1816 to mid-1817, and she was from South Carolina. The adult on her account was John Felder.
An Elizabeth Margaret Felder turns up pretty quickly in googling; she was born in 1806 in Orangeburg SC, which would make her age 10 and 11 while she was at the Mordecai school--seems like a perfect fit. Her parents were Samuel Felder and Ann Horger, first cousins, both of them born in South Carolina. Eliza's grandparents and great-grandparents were born in Switzerland and Germany. Samuel died in 1813, so the John Felder on her account was likely her older half-brother John Myers Felder (1782-1851). While Eliza was in school, John Myers Felder was serving in the South Carolina Senate.
She married lawyer Joseph Pou (1805-1888; the name was pronounced like "Pew") in 1827, and they had about seven children, two daughters and five sons. She died in Talbotton GA, in 1853, age 47. Here's her tombstone in the Talbotton City Cemetery. Her husband remarried.
Eliza's grandson, Edward William Pou (1863-1934), was a longtime member of Congress, serving continuously from 1901 to 1934. Another grandson, James Hinton Pou (1861-1935) served in the North Carolina legislature.