I know Pratt has a summer program designed for high school student as an intro to I.D. My cousin took it and loved it.
As far as portfolio, sketching is a big plus. You should get “How to Draw” written by the legendary Scott Robertson and Thomas Bertling.
They teach the technic used at Art Center College of Design. For a CAD program, the best one you can learn is Rhino 3D. It is used by most industrial design company ( apple use it and so does Mercedes…), it is relatively cheap, easy to learn, a lot of free video tutorial and widely used by professionals and it can import and export a very large amount of different files. Solidworks is also widely used, but is extremely expensive and hard to learn. The nice thing with Rhino, is you can export and import files to Solidworks, and if you know Rhino, then Solidworks will be very easy to learn…