Ev started his first company when he was a teen, and kept starting them over and over again. Biz had founded Xanga, many years before. Sure, they were over 30, i think Jack and Noah were too, when twitter got started. All of them had started earlier companies in their teen's and 20's.

Jobs also started NeXT when he was 30 after founding another well known company years before. My point is age shouldn't be a barrier to starting a company you believe in, especially not the imaginary "30" line.