That is now an SEO myth. You can hear Matt Cutts talk about it https://www.youtube.com/watch?v=-pnpg00FWJY

Again, the most important is your content and the backlinks. You may want to make alliances and friends with good site in a related industry with "presence" (DA) so they will link to your website and that will give you significant results. Directories are useful for that but industry related is even better.

Eg.: You in the tourism industry and the Tour Operator alliances list your site, you will have your site crawled quickly and have as much chances as an "old" site if you have good content.

In clear, do not worry about your domain age, but about the content and links to your site .. like a road to your house.

Speaking about SEO myths, that is a great list :
http://vope.net/seo-myths/

Hope this helps :)