That is a seemingly simple question without a simple answer.
Some folks with experience similar to yours, with sound judgement and decent natural ability could develop enough skill to use the boat safely very quickly (couple of weeks). While alternatively I've known some folks who can own a boat for years and years without ever developing a basic proficiency with her.
What I'd recommend is you hire someone with deep knowledge of both your specific vessel and if possible, your home navigation area (I believe the former is more important than the latter). A guy like Bruce Morrison has decades experience with all things Hatteras, is a natural born teacher and has successfully taught several folks on here their new vessels.
Then once you have the basics down, there is no substitute for experience. Simply, and somewhat self evidently, the more you use the boat, the easier it becomes. Amazes me, how many people miss that part.
Good Luck.