I usually look at if the site can rank #1 for the domain name itself in google. For example. type in "whateveryoursitenameis" in google search and if your not #1 then there is a good possibility it is.
Thats nothing to do with the sandbox. If your year old site should be ranking for really competitive terms ie if it has 50,000 really good links from trusted sites but still doesn't feature in the top 50 then its sandboxed.