How do we know that during Biblical times, Jewish young men wore earrings?
The Torah relates that when the Israelites saw that Moses is delayed in returning from the top of Mount Sinai, they approached Aaron the High Priest, and demanded "Come, make us a god who shall go before us." Aaron asked them to give him all their gold earrings, and after taking it from them he cast it in a mold and made it into a molten calf. That's how the Golden Calf was created.
But notice the details in Aaron's answer: