Colleges are well used to students who suddenly do something to juice up their app: starting a company, starting a club, etc. etc.etc. AdComms generally look at your ECs overall: what do you do with your time? what have you achieved? can you show increasing responsibility / leadership? did you do it, or is there heavy adult (eg parent) involvement? To paraphrase the Dir of Admissions at Princeton, they don’t care what you do- they care what you do with the experience.