Why does the author share information about Cyntoia's life before the murder with readers?

i think that it is (line 11)

marcus junius brutus, likewise called quintus caepio brutus, (conceived most likely 85 bce—kicked the bucket 42 bce, close philippi, macedonia [now in northwestern greece]), roman lawmaker, one of the pioneers in the intrigue that killed julius caesar in 44 bce. brutus was the child of marcus junius brutus (who was deceptively executed by pompey the great in 77) and servilia (who later turned into caesar's sweetheart). after his appropriation by an uncle, quintus servilius caepio, he was generally called quintus caepio brutus.