In 100,000 BBY, the Ones emerged from the mist, and became the manifestations of the balance, light side and the dark side. Before that, were there primitive species who could use the Force, and did so?
We know for a fact the many races co-existed with the Celestials around 100,000 BBY and it is widely believed the first force-users were the descendants of this powerful race. According to the Killiks, a connection was present between the Celestials and the group of Force wielders known as The Ones. it was believed that the Force wielders were descendants of the Celestials. Similarly, the Gree, Kwa and the Rakata acted as servant races to the Celestials alongside the Killiks. Together, they worked to build astonishing technological projects that ranged from the assembly of star systems to the engineering of hyperspace anomalies. It is safe to assume that before 100, 000 BBY that the Celestials were the first known race to ever deal with the Force.