Also take note the type of links to the site ranking high as the quality and position of the incoming backlinks to that site might be of higher value than it's competitors. A very important point to take note of is that the older domain had more time to build natural links of high value than the new domain. Domain age do play a role for the following reason as well
Google patent on information retrieval based on historical data. This is why domains only really start performing well in their 2nd year. But remember there are more factors at play than domain age. One way of overcoming this ranking factor is to do shotgun SEO for the first few months of a website's life. Shotgun SEO targets many non competitive keywords trying to hit as many variations of the keywords as possible in order to hit some of them, lol. one of the reasons why content rules.