Paranoid SEOs who love to blame Google for everything also love to whine about the "Google Sandbox." But, according to Google, there is no such thing. Gary Illyes reiterated that there is no Sandbox just yesterday. Now, of course, I see the irony in telling people who blame Google for everything and don't trust Google that, "Well, Google says X..." But sandbox has always stuck out to me as a particularly paranoid fantasy. As Jennifer Slegg says in the above linked article, "Do you feel your brand new site is supressed in the search results? Chances are it is either an indexing issue...or it is simply that the site doesn't have any links to give the site a boost in the results to start being visible."
So double check to make sure you aren't blocking Googlebot. And then go earn some links.