Every great idea comes from a dream and all our dreams can come true, if we have the courage to pursue them. This goes for everything in life, including start-ups and business ideas. They all start the same way but only some make it to the top. These posters by Anna Vital on Scuttlebutt and they will tell you what it takes to be on the top.
A lot of us feel the same way but end up doing nothing to change it. Just because you have never done anything exceptional does not mean you don't have it in you.
Not all of us did well in school. Honestly, it doesn't matter because school is not the only education. Here are people who dropped out to do what they did and were really good at it.