The short answer is between 30-40 for average life expectancy. It was pretty stable for at least several hundred years, not showing much movement until the late 19th century.

(Obviously there were exceptions who lived into their 70's but this is an average.)

Here's one good source of data: http://www.froebeldecade.com/lifelong-learning/

For clarification are you asking about the paleoindian period or post-1492? Because paleoindians very much participated in their own colonizing efforts around 20,000 years ago. But if you are asking about post-1492, could you be more specific in time and place? The New World is a very big place that has a long history of colonization by Europeans. Different places experienced different colonizing efforts resulting in different conditions that would have impacted life expectancy.