I bet you already know if you feel able to compete with people in their 20s. If the question is, will other people, for instance, investors, think that you're too old?
Age of founder(s) may exclude some startups from funding in California, but elsewhere the older a founder the more competent they are usually rated. Even then, more traditional funding sources, like banks, are more likely to lend or invest in older founders because of their experience and potential assets.