No, the sandbox issue doesnt really depinde much on the AGE of the domain, although this is how it appears to most webmasters. It really depindes on the type of the website your building. For example, a hosting website or a real estate website or a web directory "Millions of such sites", will take years in the sandbox and will ONLY get out of the sandbox, if its real a quality web site. If your website is about something that is hardly mentioned online, it will be out of the sandbox within months or even weeks. What im tring to say is simple, google is very smart. It will sandbox sites that are related to services/products that already have millions of sites built about it. It wont sandbox a site about a service/product that hardly has any sites built about it.