I'm not a historian or have expert knowledge in Chinese history but there is something called Paleolithic, Neolithic history in every countries. I'm presumed China's written or recorded history dates back to about 3,000 years.
And back in Pre-Shang Dynasty, it's very difficult to suggest Chinese people were formed, back in these days, Chinese people weren't exactly called "Chinese". Wasn't the name came from cathay, which derived from Khitan or Kara-Kitai which originally belonged to Khitan people who ruled Northern China under Liao-Khitan Dynasty.
Wasn't first known Chinese were from Hua tribe of China? Originated from Yellow river? Hence modern China was named "Zhong Hua Min Guo" (中華民國). Then Chinese expanded to Southward eventually absorbing Yangtze river and their tribes. The cradle of Chinese early civilizations begun from between Yellow river to Yangtze river.