I think a lot of startups get wrapped up in what they do and how they do it, or worse how others do it. They then begin to think that anything outside of this is breaking the rules. Some startup cultures even punish rule breakers. But there are no rules.
You don’t have to wait until Monday to start something. You don’t have to have a finished product before you start talking to potential customers. You don’t need to play by the rules, because there are no rules.