Prep school did wonders for Marquise Moore.

Despite leading Holy Cross to the Catholic league city championship, the 6-foot-2 guard from Queens had no Division I scholarship offers. After a big season at prep powerhouse St. Thomas More, where he developed into a true point guard, Moore drew heavy interest and is now headed to the Atlantic 10 with George Mason.

Moore, who averaged 13 points, six rebounds and five assists last season at St. Thomas More, picked Paul Hewitt’s program Thursday morning, his AAU coach Kareem Memminger told The Post.

He initially committed to Hofstra in February, but opened up his recruitment when head coach Mo Cassara was fired and replaced by Joe Mihalich. He was also considering Fairfield and Tulane..

“His potential is ahead of him,” St. Thomas More coach Jere Quinn previously said. “There’s a couple of things [he does] you can’t teach. Typically, he’s the fastest kid in the gym and he plays to win. He’s an unhappy kid when we’re losing. That’s a great quality in a basketball player.”

zbraziller@nypost.com