To give the original poster a sense of how competitive the top levels of karting are: Will Power–yes the current Indy Racing League champion–showed up at the Supernationals race in Vegas last month. He entered the SLOWEST adult class available.
And finished third.
Showing up at a national level event with little or no experience is a bit like picking up a basketball for the first time and going to the McDonalds All-American game. Who knows, you might be the next Kobe Bryant, but even he needed some experience before he could play at that level. Same with karting.