The domains will age without you doing anything, they only lose their age when they are dropped by the register. For example if you let a domain with 5 years expire without renew and then someone later decides to register it - it will start again from age zero.
Website age is something different. This is based on when a search engine first indexes the pages of the site.
So to help you. I would suggest put anything up there, even just one page of a wordpress blog. Install a sitemap plugin, submit the sitemap to google webmaster tools (or do some twitter tweets of the URL) and then googles spiders will come along and index your page. From there it will start to gain age.
EDIT: In fact the website age will be gaining right now. If you have done nothing to the domains they will point to a parking page with ads that the registers use as the default for a domain which has not had any nameservers entered for a webhost.