12 months is enough to round up your skills so that you are great at:
-explaining advanced algorithms and their results in simple terms that anyone can understand
-understanding a business problem and how to come up with an adequate solution
-adapting to different working styles so that you are a great collaborator in any team
The Analytics program at NC State's Institute for Advanced Analytics put me on the right track for data science in 11 months. Many technical skills you will have to learn on the go after you graduate, or through continuous education. But the core of being a successful data professional, you can definitely get in 12 months.