There are a lot of cases where a zero index makes sense. In physics and math there are cases where you start the index at 0 and others where you start at 1. And

There are a lot of cases where a zero index makes sense. In physics and math there are cases where you start the index at 0 and others where you start at 1. And even some where you start at -1. Which you use depends on what is most convenient for the problem at hand.