Two girls named Barrow attended the Mordecai school:
30. Olivia Barrow (1806-1857) of Tarboro NC attended the school for a year, in 1818.
31. Margaret Barrow of Tarboro NC attended the school for a year, in 1818.
Both Barrows have the name "Bennet Barrow" attached to their account.
So let's start with Bennet Barrow. Seems a Bennet Barrow (1777-1833) was born in Halifax Co., and was the son of Olivia Ruffin and William Barrow. The Ruffins are all over the extended families attached to the Mordecai school; and this particular connection gives Olivia Barrow her first name, too. Much of the extended Barrow family (Olivia Ruffin Barrow, three daughters, three sons) moved to Louisiana in 1798, by covered wagons and barges, to build some rather famous plantation homes for themselves. Two Barrow sons stayed behind in North Carolina for a while, then joined the clan. One of them was Bennet Barrow; he was listed as the cashier at the Tarboro branch of the State Bank of North Carolina, when it opened in 1811. He moved to Louisiana in 1816.
So... it's a prominent family, and it's not hard to track down the Mordecai students Olivia and Margaret. Their cousin Bennet H. Barrow (1811-1878) was a Louisiana planter and diarist. (This is another of those families where the same names are used by multiple members of the same generation; they had a brother Bennet Barrow, but his middle name was James; the diarist's father was William H. Barrow.)
Olivia Ruffin Barrow (1806-1857) was named for her late grandmother. Her father was Bennett Barrow and her mother was Martha Hill. When she attended school in Warrenton NC with her sister Margaret, their family was already mostly moved to Louisiana. She married her first cousin, William Ruffin Barrow (1800-1862). They had ten children together; five died young. They were the planters in residence at Greenwood Plantation in St. Francisville, Louisiana, which at its peak encompassed thousands of acres; the Ruffins held about 750 slaves at Greenwood. (Today the house still stands, much restored, and is open as an inn.) Here is Olivia's house on Flickr.
Margaret Barrow, Olivia's sister, "died young." "No information available." But we know something about her: she attended the Mordecai school with Olivia for a year, in 1818. One of the benefits of studying the rolls of a girls' school is that the many women who died young are still "caught" by the school's records--because their attendance was recorded, they have a bit more trace than a tombstone, or a date in a family Bible.