Age is one of the 200 parameters a search engine considers to rank your site. You get higher score if you site is older.
Older trusted sites tend to gain more respect in eyes of search engines.
The idea is that if the site thrives for longer time, probably means it has something good. Though, this is not a very big factor and you cannot rank a site just because it is old, but still is a lot more easier to get an old website ranked higher while other factors are equal.
So if you are just starting out to create a new website, think again! If you have an existing site which could be used, use it. You will have easier chances for better and higher rankings.
Want to check the age of a site? Use this Wayback Machine tool here