Find a college with a degree program in ID. Minor in art history, or architectural history. Learn SketchUp now. It's free. Volunteer for any arts and craft projects that come up at school like decorating for dances and homecoming. Find a local design group that has a summer intern program. Learn how to draw by hand to scale, and how to do a design board that shows your layout and all of the samples of the cboices being used in a room.

In other words, if you are meant to be a designer, then you will already be doing most of the things that lead you down that path because it's innate to your nature. The rest is just practice, networking, and education.