Shubham Banerjee, a 13-year-old with a creative mind, is now learning what it means to found a start-up technology business in California's Silicon Valley. He is exploring his potential market, meeting with venture capitalists, planning the launch of his first product and still attending eighth grade at the Champion School in San Jose, Calif. And it all started with Lego Mindstorms EV3 and an interest in helping blind people have access to more affordable technology.…