I struggle with this issue a lot as I have all kinds of wannabe entrepreneurs asking me for validation that they truly can make it on their own. My first response is always it depends. Success factors include having a valid business idea, good entrepreneurial skills, a source of cash, an excellent business plan, good mentors and a healthy dose of help from the universe. The Sloan brothers discuss lifestyle and workstyle factors that are also a big part of the equation.
As Michel Foucoult said, Savoir est Pouvoir (Knowlege is Power). Test your assumptions, read voraciously, surround yourself with positive and smart people and develop your plans. If your business plan doesn’t work out, at least you have learned an enormous amount that will help in your long-term career.