Does it matter if it's wrong? In mathematics it's a pretty standard, if not written, convention that for example the top left corner of a matrix has the position (1, 1) and not (0, 0). If I read an equation and saw an "a3" in it I can safely assume that there exists an a1 and an a2, all three of which are constants of some sort. I can safely assume that there does not exist an a0, because this just isn't the convention. And furthermore, when I do encounter a 0 subscript (e.g, v0), it is implicitly a special value referencing some reference value or the original starting value. This is different than if I were to see a 1 subscript, such as v1. For example, the equations

f = v0 + x

f = v1 + x

Those are the same equations right? Sure, but when I see v1 I'm not really sure what it is or could be, vs if I saw v0 I can assume it may be the initial velocity when I can look up.