If You Have A Masters In Logistics But Decided To Enlist How Do You Become An Officer Later?

The nephew of a friend of mine enlisted with a Masters In Logistics which I thought was a bit strange - with that sort of qualification I thought he would have looked at being an officer. But it seems he feels he needs to mature before taking on the leadership responsibility of an officer. After thinking about it it may not be a bad idea. But out of curiosity exactly how would he become an officer when he decides he is ready. Does that sort of qualification make is pretty much a forgone concusion or doesnt it really count for much?