It was Marcelo's mother who taught her how to sing when she was seven years old, wherein she first learned to sing "Somewhere Out There". She first performed publicly in a singing contest during her school's foundation day when she was first grade. It was also the first time that she won. She eventually joined different local singing contests around her native Quezon Province when she was eight, winning most of the time thus giving her a boost of self-esteem. She also learned to accept herself and her looks.