It is not clear who was the first person to decide to scramble an egg; however, humans have been scrambling eggs for centuries. The Ancient Romans are documented as the earliest people to scramble eggs.
The Ancient Romans were also the first group to make omelettes. Later on, the 14th century Italian book "Libro della cucina" references scrambled eggs: "There is so much known about fried, roasted, and scrambled eggs that it is not necessary to speak about them." Unfortunately, there is no way of ever knowing who was the actual inventor of scrambled eggs.